ES confidence level, percent Expected Shortfall, Confidence Level Percentage Expected Shortfall, Confidence Level Percentage CHF Switzerland, Francs Disclosure of contingent liabilities [line items] Disclosure of contingent liabilities [line items] Proportion of ownership interest in subsidiary, announced for sale Proportion Of Ownership Interest In Subsidiary, Announced For Sale Proportion Of Ownership Interest In Subsidiary, Announced For Sale Ratio of executive directors’ total remuneration to underlying attributable profit Ratio Of Executive Directors Total Remuneration To Underlying Attributable Profit Ratio Of Executive Directors Total Remuneration To Underlying Attributable Profit Tangible assets Purchase of property, plant and equipment, classified as investing activities Public fixed income Public Fixed Income Debt Securities [Member] Public Fixed Income Debt Securities. Other operating income Other operating income Other Operating Income (Expense), Segment Reporting The amount of other operating income (expense) used for segment reporting, which includes dividend income, income from companies using the equity method, other operating income, other operating expense, and income and expense under insurance and reinsurance contracts. Wages and salaries Wages and salaries 2021 variable remuneration Share Based Variable Remuneration Award 2021 [Member] Share Based Variable Remuneration Award 2021 Non-controlling interests Abstract Non-Controlling Interests [Abstract] No definition available. Entity File Number Entity File Number Forborne loan portfolio Forborne Loan Portfolio [Member] This member stands for the forborne loan portfolio. RON/EUR Romania, New Lei And Euro [Member] Romania, New Lei And Euro Schedule of insurance contracts linked to pensions Disclosure Of Amounts Arising From Insurance Contracts Linked To Pensions [Table Text Block] Disclosure of amounts rising from insurance contracts linked to pensions. Increase in accrued interest Subordinated Issue, Increase, Accrued Interest Increase for accrued, but unpaid interest on the subordinated issues for the period. Disclosure of detailed information about intangible assets Disclosure of detailed information about intangible assets [text block] Liability for incurred claims (LIC) Liabilities for incurred claims [member] Levels of fair value hierarchy [domain] Levels of fair value hierarchy [domain] Mortgage loans, provision and adjustment to gross carrying amount Mortgage Loans, Denominated In/Indexed To Swiss Francs, Provisions And Adjustment To Gross Carrying Amount Mortgage Loans, Denominated In/Indexed To Swiss Francs, Provisions And Adjustment To Gross Carrying Amount Tangible and intangible assets Losses On Disposals Of Tangible And Intangible Assets Not Classified As Held For Sale Amount of losses on disposals of tangible and intangible assets not classified as held for sale during the period. Provisions recognized to cover expenses of pre-retirement and voluntary redundancy offers Provisions Recognized To Cover Expenses Of Pre Retirement And Voluntary Redundancy Offers Provisions recognized to cover expenses of pre-retirement and voluntary redundancy offers. Net defined benefit liability (asset) [axis] Net defined benefit liability (asset) [axis] Consideration, in cash per American Depositary Share Consideration, In Cash Per American Depositary Share Consideration, In Cash Per American Depositary Share Number of different blocks Deferred Variable Remuneration, Number Of Different Blocks Deferred Variable Remuneration, Number Of Different Blocks Domestic systemic entities, capital buffer percentage Domestic Systemically Important Entities, Capital Buffer Percentage Domestic Systemically Important Entities, Capital Buffer Percentage Change in provision assuming 100bp decrease in interest rate (as a percent) Percent Change In Provision Assuming 100 Basis Point Decrease In Interest Rate Percent Change In Provision Assuming 100 Basis Point Decrease In Interest Rate TSR minimum metric, result Variable Remuneration, Deferred Payment, TSR Minimum Metric, Result Variable Remuneration, Deferred Payment, TSR Minimum Metric, Result Default rate expected increase (in percentage) Default Rate, Expected Increase, Percentage Default Rate, Expected Increase, Percentage Structural VaR Structural Risks [Member] This member stands for the risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in market prices for structural balance sheet components (excluding assets and liabilities held for trading). Hedging derivatives Derivatives Designated As Hedging Instruments Category [Member] This member stands for the derivatives designated as hedging instruments category of financial assets or liabilities. Other operating income Other operating income Non-interest income Other Operating Income1 Other Operating Income1 Other executives Other Executive Personnel [Member] This member stands for other executive personnel, not otherwise disclosed, of the entity. Effect of profit or loss of associates and joint ventures Tax Effect Of Profit (Loss) Of Associates And Joint Ventures Tax Effect Of Profit (Loss) Of Associates And Joint Ventures Changes in the fair value of equity instruments measured at fair value through other comprehensive income Other comprehensive income, net of tax, gains (losses) from investments in equity instruments Sales/Settlements Sales, fair value measurement, assets Other remuneration Key Management Personnel Compensation, Other Employee Benefits The amount of compensation to key management personnel in the form of other employee benefits. Chairman and CEO Board Of Directors Chairman And Chief Executive Officer [Member] Board Of Directors Chairman And Chief Executive Officer Other equity instruments and own shares Disclosure of treasury shares [text block] FINANCIAL ASSETS DESIGNATED AT FAIR VALUE THROUGH PROFIT OR LOSS Financial assets at fair value through profit or loss Financial assets at fair value through profit or loss, designated upon initial recognition or subsequently, category [member] INTANGIBLE ASSETS Intangible assets Intangible assets and goodwill Unrated Unrated [Member] Unrated. Spanish legislation Spanish Legislation [Member] Spanish Legislation Commission expense Disclosure Of Fee And Commission Expenses [Text Block] The disclosure of fee and commission expenses. Statement of comprehensive income [abstract] Statement of comprehensive income [abstract] Average selling price of bank shares (in euro per share) Weighted Average Share, Selling Price The weighted average selling price per share. Coming from non-banking financial products Fee And Commission Income, Marketing Of Nonbanking Financial Products [Abstract] n/a. Of which other collateral Other Than Property Collateral Pledged [Member] Pledge of other assets rather than property to serve as protection against default. Changes in the RV hedged with micro-hedging transactions Gains (Losses) On Financial Assets Measured At Fair Value Through Other Comprehensive Income, Changes In The RV Hedged, Before Tax Gains (Losses) On Financial Assets Measured At Fair Value Through Other Comprehensive Income, Changes In The RV Hedged, Before Tax Number of subsidiaries tax resident in the UK, liquidated during period Number Of Subsidiaries Tax Resident In The UK, Liquidated During Period Number Of Subsidiaries Tax Resident In The UK, Liquidated During Period Schedule of debt instruments by origin of issuer Disclosure Of Debt Instruments By Origin Of Issuer [Table Text Block] The disclosure of debt instruments by origin of issue. Cash paid, deferred Key Management Personnel Compensation, Cash Payment Deferred Remuneration The amount of Key Management Personnel Compensation Cash Payment, deferred Remuneration Other financial liabilities Other Financial Liabilities, Unspecified The amount of financial liabilities described as other that are not specifically identified in the disclosure. Interest income Disclosure of interest income [text block] Issuance of debt securities Proceeds from issue of bonds, notes and debentures Other equity instruments issued Other Equity Instruments Issued Other Equity Instruments Issued Legal reserve Statutory reserve Relative TSR metric, achievement rate Variable Remuneration, Deferred Payment, Relative TSR Metric, Achievement Rate Variable Remuneration, Deferred Payment, Relative TSR Metric, Achievement Rate NON-TRADING FINANCIAL ASSETS MANDATORILY AT FAIR VALUE THROUGH PROFIT OR LOSS Non-trading financial assets mandatorily at fair value through profit or loss Non-trading financial assets mandatorily at fair value through profit or loss Financial assets at fair value through profit or loss, mandatorily measured at fair value Banque Stellantis France Banque Stellantis France [Member] Banque Stellantis France Senior Management Senior Management [Member] This member stands for those persons identified as senior management having authority and responsibility for planning, directing and controlling the activities of the entity, directly or indirectly, of that entity. Off-shore entities Off Shore Entities [Member] Represents information pertaining to subsidiaries resident in off-shore territories. Impairment (Note 12) Non-Current Assets Held For Sale, Valuation Allowance Charges Charges for the period against the valuation allowance for non-current assets held for sale. Provisions or reversion of provisions Increase (Decrease) Through Extraordinary Provisions Extraordinary provisions. Other valuation adjustments Other Valuation Adjustments, Not Reclassified To Profit Or Loss, Net Of Tax Other Valuation Adjustments, Not Reclassified To Profit Or Loss, Net Of Tax Gains or losses resulting from the accounting for hedges of equity instruments measured at fair value through other comprehensive income, net Other comprehensive income, net of tax, gains (losses) on hedging instruments that hedge investments in equity instruments Corporate Centre Corporate Center [Member] Represents Corporate center. Types of Assets [Domain] Types Of Assets [Domain] This member stands for aggregated types of assets. Increase (decrease) in nonperforming coverage ratio Increase (Decrease) In Non-Performing Coverage Ratio, Percent Increase (Decrease) In Non-Performing Coverage Ratio, Percent Classes of intangible assets other than goodwill [axis] Classes of intangible assets other than goodwill [axis] Percentage decrease in non-performing loans ratio Decrease In Non-Performing Loans Ratio The decrease during the period in the nonperforming loans ratio, as a percent. Santander Vida Seguros y Reaseguros, S.A. Santander Vida Seguros Y Reaseguros [Member] Santander Vida Seguros Y Reaseguros Liabilities under insurance contracts Disclosure of insurance contracts [text block] Discontinued operations, consolidated balance sheet Discontinued Operations, Consolidated Balance Sheet [Table Text Block] Discontinued Operations, Consolidated Balance Sheet SHARE PREMIUM Share premium account Share Premium Share premium 3. Cash flows from financing activities Cash flows from (used in) financing activities [abstract] Charge to the participants Charge To The Participants Charge to the participants. Large companies Corporate Loans To Large Companies [Member] This member stands for loans made to large companies. Additional disclosures Disclosure Of Parent Financial Statements And Preference Shares And Preferred Securities [text block] The entire disclosure for parent financial statements, preference shares and preferred securities. Provisions For Employee Benefits And Others [Domain] Provisions For Employee Benefits And Others [Domain] This member stands for provisions for employee benefits and other provisions. Total assets encumbered Total Encumbered Assets, Carrying Value The amount of total assets encumbered in funding transactions under EBA standards (total assets plus collateral received). No Rating No Rating [Member] No Rating Deposits [Table] Disclosure Of Deposits [Table] Deposits [Table] Schedule of remainder of financial assets, liabilities and memorandum item by maturity Schedule Of Maturities Of Financial Assets Liabilities And Memorandum Items Recognised At Other Than Amortised Cost [Table Text Block] Tabular disclosure of maturities of financial assets, liabilities and memorandum items that are recognised at other than amortized cost. Total recognised income and expenses for the year Total recognised income and expense Other comprehensive income Comprehensive income Disclosure of maturity analysis for financial assets held for managing liquidity risk [line items] Disclosure of maturity analysis for financial assets held for managing liquidity risk [line items] Diluted earnings (loss) per share from continuing operations (in euro per share) Diluted earnings (loss) per share from continuing operations Securities and interest rate futures Securities And Interest Rate Futures [Member] Securities And Interest Rate Futures [Member] Deferred payment, percentage paid in share options Variable Remuneration, Deferred Payment, Percentage Paid In Share Options Variable Remuneration, Deferred Payment, Percentage Paid In Share Options Schedule of funding status of the defined benefit obligations Disclosure of net defined benefit liability (asset) [text block] Inflation risk Inflation Risk [Member] Information pertaining to inflation risk. Net amount of financial liabilities presented in the balance sheet Net financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position Market value Derivative Fair Value Derivative fair value. Senior executives Senior Executives [Member] This member represents senior executives. Excludes other executives. Issued by Private-sector Debt Instruments Issued By Private Sector [Member] This member stands for instruments issued by private sector companies held by the entity that represent indebtedness. Disclosure of reconciliation of changes in insurance contracts by remaining coverage and incurred claims [line items] Disclosure of reconciliation of changes in insurance contracts by remaining coverage and incurred claims [line items] Foreign currency options Foreign Currency Options [Member] This member stands for foreign currency options. Digital Transformation Award 2021 Digital Transformation Award 2021 [Member] Digital Transformation Award 2021 Disclosure of transferred financial assets that are not derecognised in their entirety [line items] Disclosure of transferred financial assets that are not derecognised in their entirety [line items] Merlin Properties, SOCIMI, S.A. Merlin Properties Socimi S.A. [Member] Merlin Properties, SOCIMI, S.A. [Member] CMS10 CMS 10 Interest Rate [Member] This member stands for CMS 10 Interest rate. Banco Santander Totta, S.A. Banco Santander Totta, S.A. [Member] Represents information pertaining to Banco Santander Totta SA., a subsidiary of the entity. Other financial liabilities, total Other financial liabilities Other financial liabilities Income tax Description of accounting policy for income tax [text block] Macro cash flows hedge, position Macro Cash Flows Hedge, Hedged Position Macro Cash Flows Hedge, Hedged Position Banco Santander, S.A. Parent Company [Member] Deductions Eligible Capital, Deductions The amount of adjustments to equity required for computation of Common Equity Tier I (CET I) equity. Gains on litigation settlements Gains on litigation settlements Estimated collateral value Estimated Collateral Held Value Estimated value of collaterals held which are associated with loan receivables. Income from insurance and reinsurance contracts Income From Insurance And Reinsurance Contracts Recognised In Profit Or Loss Amount of income from assets included in profit or loss under insurance contracts and reinsurance contracts issued. Lead independent director Lead Director [Member] This member stands for the person serving as the coordinating director of the board of directors. Acquisition for the year (net) Increase (Decrease) Through Business Combinations Deferred Tax Liability The increase (decrease) in deferred tax liability resulting from business combinations Dilutive effect of options/rights on shares (in shares) Dilutive Effect Of Share Options And Share Rights On Number Of Ordinary Shares The number of dilutive potential ordinary shares that relate to the assumed exercise of the entity's share options and the effect of share rights. Gains (losses) on disposal of subsidiaries Gains (Losses) On Disposal Of Subsidiaries Gains (Losses) On Disposal Of Subsidiaries Percentage of loans secured Loans And Advances To Customers, Secured Percentage The percentage of loans secured by mortgages or other collateral. Disclosure of detailed information about business combination [abstract] Disclosure of detailed information about business combination [abstract] Percentage of total provisions for the most relevant units of the Group Percentage Of Total Provisions Percentage Of Total Provisions Provision For Compensation And Associated Cost In Respect Of PPI Policies Provision For Compensation And Associated Cost In Respect Of PPI Policies [Member] Provision For Compensation And Associated Cost In Respect Of PPI Policies Liabilities subject to netting and collateral arrangements on balance sheet Net financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements Forward rate agreements Forward contract [member] Schedule of detail, by classification, of loans and advances to customers Disclosure Of Loans And Advances To Customers [Table Text Block] Tabular disclosure of loans and advances to customers. Compensation received as strategic adviser Key Management Personnel Directors Compensation Received As Strategic Adviser Key Management Personnel Directors Compensation Received As Strategic Adviser Customer Deposits [Table] Disclosure Of Customer Deposits [Table] Customer Deposits [Table] Non-trading financial assets mandatorily at fair value through profit or loss Adjustments For Decrease Increase In Non-trading Financial Assets Mandatorily At Fair Value Through Profit Or Loss Adjustments for decrease (increase) in non-trading financial assets mandatorily at fair value through profit or loss to reconcile profit (loss) to net cash flow from (used in) operating activities. Tangible and intangible assets Gains On Disposals Of Tangible And Intangible Assets Not Classified As Held For Sale Amount of gains (losses) on disposals of tangible and intangible assets not classified as held for sale during the period. Interest expense (note 39) Increase Through Pension Interest Expense, Provision Provision for pension interest expense. Short-term debt Current borrowings Santander Consumer Bank AG Santander Consumer Bank AG [Member] This member stands for Santander Consumer Bank AG. Debt instruments at fair value with changes in other comprehensive income Changes in the fair value of debt instruments measured at fair value with changes in other comprehensive income Net revaluation gains/ (losses) Reserve of gains and losses on financial assets measured at fair value through other comprehensive income Classes of other provisions [domain] Classes of other provisions [domain] Changes in capital and others concepts Increase (Decrease) Due To Changes In Capital And Other Changes The increase (decrease) in equity resulting from changes in capital and other changes that the entity does not separately disclose in the same statement or note. Deferred payment, ROE objective, weight Variable Remuneration, Deferred Payment, RoTE Objective, Weight Variable Remuneration, Deferred Payment, RoTE Objective, Weight Chair of the audit committee Audit Committee, Chairman [Member] This member stands for the person serving as chairman of the audit committee of the board of directors. Disclosure of external credit grades [table] Disclosure of external credit grades [table] Actuarial (gains)/losses recognised in the year Actuarial Gains Losses Recognized Related To Defined Benefit Actuarial (gains)/losses recognized in the year related to defined benefits. Schedule of impairment loss and allowance for loans and advances to customers Disclosure Of Impairment Loss And Allowance For Loans And Advances To Customers [Table Text Block] Disclosure of impairment loss and allowance for loans and advances to customers. Disclosure of reconciliation of changes in goodwill [line items] Disclosure of reconciliation of changes in goodwill [line items] Crédit Agricole S.A. Crédit Agricole S.A. [Member] Crédit Agricole S.A. Subordinated liabilities Proceeds from issue of subordinated liabilities TOTAL FINANCIAL LIABILITIES Total Financial Liabilities Remaining The amount of remaining total financial liabilities including financial liabilities held for trading, financial liabilities designated at fair value through profit or loss, hedging derivatives and changes in the fair value of hedged items in portfolio hedges of interest rate risk. Constant Maturity Swap (CMS) Constant Maturity Swap (CMS) [Member] Constant Maturity Swap (CMS) IT developments Technology-based intangible assets [member] Construction in progress and other items Construction in progress Construction in progress [member] 3 to 12 months Three months to one year Later than three months and not later than one year [member] ASSETS Assets FINANCIAL ASSETS Assets [abstract] Maximum percentage of eligible capital allowed under regulation Large Exposure, Maximum Percentage Of Eligible Capital The maximum percentage of eligible capital allowed by regulation for a customer or group of connected customers defined as a "Large Exposures" in CRR (Regulation (EU) No 575/2013). Number of geographies with global merchant services platform Deferred Variable Remuneration, Milestone, Number Of Geographies With Global Merchant Services Platform Deferred Variable Remuneration, Milestone, Number Of Geographies With Global Merchant Services Platform 1 % appreciation of euro, effect on consolidated profit Decrease In Consolidated Profit Due To Reasonably Possible Appreciation Of Entity's Functional Currency The estimated decrease in consolidated profit that would have been caused by an appreciation of entity's functional currency that was reasonably possible at the end of the reporting period. Transfers into Level 3 of fair value hierarchy, liabilities Transfers into Level 3 of fair value hierarchy, liabilities Santander Holdings USA, Inc. Santander Holdings USA, Inc. [Member] Santander Holdings USA, Inc. Other adjustments Regulatory Capital, Other Adjustments Amount of other assets and liabilities excluded from regulatory capital. Remeasurement of disposal group or assets held for sale, write-off Remeasurement of Disposal Group or Assets Held for Sale, Write-off Remeasurement of Disposal Group or Assets Held for Sale, Write-off Pamela Walkden Pamela Ann Walkden [Member] Ms. Pamela Ann Walkden [Member] Other fees and commissions Other fee and commission expense External credit grades [axis] External credit grades [axis] Technology and systems Technology Systems Expense The amount of expense relating to technology and systems. Liabilities secured by financial assets Liabilities Secured By Financial Assets The amount of liabilities that are secured by financial assets of the entity. Total phase-in capital Total capital coefficient IFRS Capital To Risk Weighted Assets Total Capital divided by risk weighted assets as defined in the international regulations. Minimum Group's economic capital Variable Remuneration, Minimum Group's Economic Capital Variable Remuneration, Minimum Group's Economic Capital Recoveries Noncurrent Assets Held For Sale, Tangible Assets, Valuation Allowance Recoveries The amount of recoveries during the period for the valuation allowance for noncurrent assets held for sale. Disclosure of reserves within equity [table] Disclosure of reserves within equity [table] Items that will not be reclassified to profit or loss ITEMS THAT WILL NOT BE RECLASSIFIED TO PROFIT OR LOSS: Other Comprehensive Income, Items That Will Not Be Reclassified To Profit Or Loss Amount of other reserves not reclassified to profit or loss that is attributable to parent. Santander International Products, Plc. Santander International Products PLC [Member] Represents information pertaining to Santander International Products, Plc, a subsidiary of the entity. Coverage rate NPL coverage ratio Non-Performing Coverage Ratio The percentage of instruments classified as non-performing that are covered by a provision against losses, calculated as the amount of provisions for coverage of impairment losses on loans and advances to customers and contingent liabilities (without country risk) divided by the amount of loans and advances to customers and nonperforming contingent liabilities (without country risk). Digital Transformation Award 2022, second block Digital Transformation Award 2022, Second Block [Member] Digital Transformation Award 2022, Second Block Derivatives [Abstract] Derivatives [Abstract] n/a Pillar 2 percentage Common Equity Pillar Two Capital Ratio Percentage of Common Equity Pillar 2 Risk-based Capital to total risk-weighted assets, as defined by regulatory framework. Repurchase agreements Repurchase Agreement [Member] Information pertaining to repurchase agreements. Credit impairment of financial instruments [axis] Credit impairment of financial instruments [axis] Legal case relating to questionable deduction of loan losses in income tax returns Legal Case Relating To Questionable Deduction Of Loan Losses In Income Tax Returns [Member] This member stands for contingent liabilities relating to legal cases, including predecessors, appeal the assessments of government relating to deduction of expenses such as loan losses or goodwill written off in the company's income tax returns (IRPJ and CSLL) on the ground that the relevant requirements under the applicable legislation were not met. Financial assets with modified contractual cash flows while loss allowance measured at lifetime expected credit losses Financial assets with modified contractual cash flows while loss allowance measured at lifetime expected credit losses for which loss allowance changed during reporting period to 12-month expected credit losses, gross carrying amount Disclosure of analysis of other comprehensive income by item [line items] Items that may be reclassified to profit or loss Disclosure of analysis of other comprehensive income by item [line items] Deferred conditional variable remuneration plan and linked to objectives (2021) Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2021 [Member] Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2021 Related party transactions [abstract] Equity instruments Equity investments [member] 2. Cash flows from investing activities Cash flows from (used in) investing activities [abstract] Award, number of shares (in shares) Number of instruments granted in share-based payment arrangement Dividends proposed, total per share (in eur per share) Dividends proposed or declared before financial statements authorised for issue but not recognised as distribution to owners per share Redemption of treasury shares, purchase value Redemption Of Treasury Shares, Purchase Value Redemption Of Treasury Shares, Purchase Value Eligible instruments AT1 Eligible Capital Eligible Instruments Additional Tier One The amount of eligible instruments, at Additional Tier One level, that is combined with Tier One excesses, residual value of dividends and other deductions to determine Additional Tier One capital. Other retained earnings Other Retained Earnings A component of equity representing the entity's cumulative other comprehensive undistributed earnings or deficit. Unmatured Unmatured [Member] This member stands for unmatured time band. Loans and advances to customers Loans And Advances, Customers, Excluding Poland Disposal [Member] Loans And Advances, Customers, Excluding Poland Disposal Deferred variable remuneration Deferred Conditional Variable Remuneration Plan [Member] Information pertaining to the deferred variable compensation plan (bonus). Banco Santander México, S.A., Institución de Banca Múltiple, Grupo Financiero Santander México Grupo Financiero Santander (México) Banco Santander Mexico S.A. Institucion De Banca Multiple, Grupo Financiero Santander Mexico [Member] Represents information pertaining to Banco Santander (Mexico), S.A., Institucion de Banca Multiple, Grupo Financiero Santander Mexico, a subsidiary of the entity. Percentage of portfolio with LTV less than defined percent Percentage Of Portfolio With Loan To Value Ratio Less Than Defined Percent Percentage of portfolio with loan to value ratio of less than defined percentage. (Charge)/Credit to income Deferred Tax Income Recognised In Profit or Loss The amount of tax expense or income relating to changes in deferred tax assets, recognised in profit or loss. Pessimistic scenario 3 Pessimistic Scenario Three [Member] Pessimistic Scenario Three Number of employees - others Number Of Others Employees Number Of Others Employees VaR Value at risk Surveillance and cash courier services Surveillance And Courier Services Expense The amount of expense relating to surveillance and courier services. Deferred payment, short term, percentage paid in shares Variable Remuneration, Deferred Payment, Short Term, Percentage Paid In Shares Variable Remuneration, Deferred Payment, Short Term, Percentage Paid In Shares Non current assets Non-current assets Banco RCI Brasil S.A. Banco RCI Brasil S.A. [Member] Banco RCI Brasil S.A. Changes in financial instruments, Liabilities Reconciliation of changes in fair value measurement, liabilities [abstract] Cash flow hedges (effective portion) Other comprehensive income, before tax, cash flow hedges Amounts transferred to income statement Reclassification adjustments on hedges of net investments in foreign operations, before tax CIP S.A. CIP S.A. [Member] CIP S.A. Profit net of dividends Profit (Loss), Net Of Dividends The total of income less expenses, excluding the components of other comprehensive income and net of dividends. Other beneficiaries Other Beneficiaries [Member] Represents other beneficiaries with variable remuneration. Classes of property, plant and equipment [axis] Classes of property, plant and equipment [axis] Number of subsidiaries resident in off-shore territories Number Of Subsidiaries Resident In Off-Shore Territories The number of subsidiaries resident in off-shore territories. Gains (losses) on financial transactions Other gains (losses) Cash-generating units [axis] Cash-generating units [axis] Up to one month 1 month Not later than one month [member] Actuarial assumptions [domain] Actuarial assumptions [domain] Disclosure of reclassifications or changes in presentation [abstract] Disclosure of reclassifications or changes in presentation [abstract] TSR maximum metric, target Variable Remuneration, Deferred Payment, TSR Maximum Metric, Target Variable Remuneration, Deferred Payment, TSR Maximum Metric, Target Internally Adapted Credit Grades [Axis] Internally Adapted Credit Grades [Axis] Internally Adapted Credit Grades Joint venture entities Investments in joint ventures accounted for using equity method Deferred payment, percentage paid in cash Variable Remuneration, Deferred Payment, Percentage Paid In Cash The percentage of an award granted under a variable remuneration deferred payment plan paid in cash. EFFECT OF FOREIGN EXCHANGE RATE CHANGES D) Effect of foreign exchange rate differences Effect of exchange rate changes on cash and cash equivalents Mortgage-backed bonds loan-to-value ratio for home loans (as a percent) Mortgage Backed Bonds Loan To Value Ratio Home Loans Represents the required loan-to-value ratio for mortgage-backed bonds for home loans. Foreign currency transactions Description of accounting policy for foreign currency translation [text block] SMEs and Corporates Small And Medium Entities And Corporates [Member] Small And Medium Entities And Corporates [Member] Communications Communication expense Other concepts, deferred tax assets not recognized Other Concepts, Deferred Tax Assets Not Recognized Other Concepts, Deferred Tax Assets Not Recognized Demand accounts Credit Related Fee And Commission Income Demand Accounts The amount of income recognised from credit-related fees and commissions from demand accounts. Maximum number of shares to be delivered at beginning of period (in shares) Maximum number of shares to be delivered at end of period (in shares) Number Of Shares Earned In Share-Based Payment Arrangement The number of share to be delivered in a share-based payment arrangement. Percentage of reasonably possible increase in actuarial assumption Percentage of reasonably possible increase in actuarial assumption Percentage of entity's total non-current assets held for sale Non-Current Assets Classified As Held For Sale, Percentage Percentage of entity's total non-current assets classified as held for sale. Disclosure of detailed information about financial instruments [table] Disclosure of detailed information about financial instruments [table] Increase in fair value assets due to changes in inputs Increase in fair value measurement due to change in multiple unobservable inputs to reflect reasonably possible alternative assumptions, liabilities To stage 2 from stage 3 To stage 3 from stage 2 Increase (Decrease) Through Transfers From Stage 3 To Stage 2 Financial Assets The increase (decrease) in financial assets resulting from transfers from credit risk stage 3 to stage 2. Loans And Advances To Customers [Line Items] Loans And Advances To Customers [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Deferred payment, number of annuities Variable Remuneration, Deferred Payment, Number Of Annuities Variable Remuneration, Deferred Payment, Number Of Annuities Other payments related to financing activities Other Outflows Of Cash Classified As Financing Activities Outflows of cash, classified as financing activities, that the entity does not separately disclose in the same statement or note. Property securities Property Securities [Member] Property Securities Number of credit risk categories Number Of Credit Risk Categories Number Of Credit Risk Categories Memorandum Items [Domain] Memorandum Items [Domain] Memorandum Items [Domain] Other risks Other Risks [Member] This member stands for other types of risk not separately disclosed. Schedule of loans and advances to customers in detail by activity Disclosure Of Loans And Advances To Customers In Detail By Activity [Table Text Block] Tabular disclosure of loans and advances to customers in detail by activity. Condensed Income Statement [Table] Condensed Income Statement [Table] Issuance By Banco Santander Brasil In December 2025 Issuance By Banco Santander Brasil In December 2025 [Member] Issuance By Banco Santander Brasil In December 2025 Disclosure of maturity analysis of operating lease payments [table] Disclosure of maturity analysis of operating lease payments [table] Disclosure of attribution of expenses by nature to their function [line items] Disclosure of attribution of expenses by nature to their function [line items] Number of sales programs with conversion rate optimization roll-out Deferred Variable Remuneration, Milestone, Number Of Sales Programs With Conversion Rate Optimization Roll-Out Deferred Variable Remuneration, Milestone, Number Of Sales Programs With Conversion Rate Optimization Roll-Out Proceeds Inflows Of Cash From Financing Activities The cash inflow from financing activities. Chilean peso Chile, Pesos Individually calculated Expected credit losses individually assessed [member] Levels of fair value hierarchy [axis] Levels of fair value hierarchy [axis] American depositary receipt, share equivalent (in shares) American Depositary Receipt, Share Equivalent Number of entity shares equivalent to an American Depositary Receipt (BDR) listed on the New York Stock Exchange. Consideration paid (received) Consideration paid (received) Offsetting of financial instruments Description of accounting policy for offsetting of financial instruments [text block] Impairment or reversal of impairment of investments in subsidiaries, joint ventures and associates, net Impairment Loss Reversal Of Impairment Of Investments In Subsidiaries Joint Ventures And Associates, Net Net amount of impairment loss or reversal of impairment of investments in subsidiaries, joint ventures and associates recognized in profit or loss. Buildings under construction Buildings And Other Constructions Under Construction [Member] This member stands for construction and property development loans related to projects under construction. Issuance By Banco Santander S.A. In March 2025 Issuance By Banco Santander S.A. In March 2025 [Member] Issuance By Banco Santander S.A. In March 2025 Disclosure of detailed information about hedged items [line items] Disclosure of detailed information about hedged items [line items] Capital insured by life and accident insurance Life And Accident Insurance, Coverage Limit Coverage limit provided by the insurance arrangement for life and accident insurance claims. Gross amount of financial assets offset in the balance sheet Gross financial liabilities set off against financial assets subject to offsetting, enforceable master netting arrangements or similar agreements Administration and custody Brokerage Fee Income Administration And Custody The amount of income recognised for brokerage fees charged by the entity from administration and custody. Equity Investments Investments accounted for using equity method [member] Called up paid capital Called Up Paid Capital Called Up Paid Capital Schedule of financial information on the subsidiaries with significant non-controlling interests Disclosure Of Non-Controlling Interest Financial Information Explanatory [Table Text Block] The disclosure of financial information on subsidiaries with significant non-controlling Interests. Schedule of fair values of financial assets and liabilities Disclosure Of Fair Value Measurement Of Assets And Liabilities [Table Text Block] The disclosure of the fair value measurement of assets and liabilities. Buy to let mortgages, mortgage portfolio, percentage Buy To Let Mortgages, Mortgage Portfolio, Percentage Buy To Let Mortgages, Mortgage Portfolio, Percentage Holding period for shares issued in settlement of pension obligations Payments In Respect Of Settlements, Net Defined Benefit Liability (Asset), Holding Period The holding period for shares issued in settlement of defined-benefit pension obligations. Entity Central Index Key Entity Central Index Key Proceeds Divestments (+) Inflows of cash from investing activities Increase through other costs associated Increase (Decrease) Through Other Costs Associated, Other Provisions Increase (Decrease) Through Other Costs Associated, Other Provisions Other payments related to investing activities Other Payments Of Cash, Classified As Investing Activities Other Payments Of Cash, Classified As Investing Activities Commissioned services from audit firms Professional fees expense Trading derivatives (assets and liabilities) and short positions Disclosure Of Trading Derivatives And Short Positions [Text Block] The disclosure of derivatives (assets and liabilities) and short positions. Adjustments related to the Poland disposal Adjustment Due To Poland Disposal [Member] Adjustment Due To Poland Disposal Effect of curtailment/settlement Effect Of Curtailment Settlement Defined Benefit Liability Asset Effect of curtailment/settlement on defined benefit liability asset. Other results and provisions Other Results And Provisions Other Results And Provisions Risk exposure associated with instruments sharing characteristic Excess of gross exposure over maximum recoverable amount of effective collateral Risk exposure Risk exposure associated with instruments sharing characteristic Number of trading sessions Variable Remuneration, Weighted Average Share Prices, Number Of Trading Sessions The number of trading sessions used in calculation of volume-weighted average share prices. Insurance premiums Insurance expense Senior unsecured debt Senior Unsecured Debt [Member] Senior Unsecured Debt [Member] OECD OECD [Member] OECD Schedule of goodwill and changes in goodwill Disclosure of reconciliation of changes in goodwill [text block] Exposure Tier One Leverage Capital Exposure, Average Assets Amount of average assets, as calculated in accordance with international regulatory capital standards. Revaluation gains (losses) Gains (losses) on cash flow hedges, before tax Discounted Cash Flows Discounted cash flow [member] Rest of equity Rest Of Equity Rest Of Equity Positive impact on CET1 Positive Impact On Common Equity Tier One Capital Radio Positive Impact On Common Equity Tier One Capital Radio Method of assessment of expected credit losses [axis] Method of assessment of expected credit losses [axis] Disclosure of changes in financial assets at fair value through other comprehensive income Disclosure Of Changes In Financial Assets At Fair Value Through Other Comprehensive Income [Table Text Block] Disclosure Of Changes In Financial Assets At Fair Value Through Other Comprehensive Income Attendance Fees And Commissions Attendance Fees And Commissions [Member] Attendance Fees And Commissions Disclosure of changes in bonds and debentures outstanding Disclosure Of Changes In Bonds And Debentures Outstanding [Table Text Block] Disclosure Of Changes In Bonds And Debentures Outstanding Adjustments due to errors Increase (decrease) due to corrections of prior period errors [member] Deferred tax assets not recognized Deferred Tax Assets Not Recognized The amount of deferred tax assets subject to requirements not recognized for the period. B) Cash flows from investing activities Cash flows from (used in) investing activities, discontinued operations Internally Adapted Credit Grades [Domain] Internally Adapted Credit Grades [Domain] Internally Adapted Credit Grades [Domain] Decrease due to other modification Increase (decrease) in net defined benefit liability (asset) resulting from miscellaneous other changes Insurance contracts by remaining coverage and incurred claims [axis] Insurance contracts by remaining coverage and incurred claims [axis] Schedule summarising remuneration related to multi-annual variable objectives Disclosure Of Transactions Between Related Parties, Remuneration, Variable Objective Explanatory [Table Text Block] Tabular disclosure of remuneration by director for multiannual objectives between the entity and its related parties. Financial liabilities held for trading Financial liabilities at fair value through profit or loss that meet definition of held for trading, category [member] Transfer, exchange differences and other changes Increase (Decrease) Through Transfer, Exchange Differences And Other Changes, Provisions Increase or decrease to provisions due to transfer, exchange differences and other changes Minimum percentage of increased share capital required to be maintained in the legal reserve if reserves are used to increase capital Minimum Percentage Of Increased Share Capital Required To Be Maintained In Legal Reserve Minimum percentage of the increased share capital required to be maintained in the legal reserve if reserves are used to increase capital. Amount paid for retirement pension benefit Benefits paid or payable Own debt securities issued other than own covered bonds or ABSs Entity Own Equity Instruments Other Than Covered Bonds And Asset Backed Securities [Member] This member stands for equity instruments issued by the entity except covered bonds and asset-backed securities (ABS). Subordinated issue, euro swap rate term Subordinated Issue, Euro Swap Rate Term Subordinated Issue, Euro Swap Rate Term Expected consideration per American Depositary Share (in MXN per share) Expected Consideration, In Cash Per American Depositary Share Expected Consideration, In Cash Per American Depositary Share Commission income Commission Income, Related Party Transactions The amount of commission income attributable to related party transactions. Change in provision assuming 100bp increase in unemployment rate (as a percent) Percent Change In Provision Assuming 100 Basis Point Increase In Unemployment Rate Percent Change In Provision Assuming 100 Basis Point Increase In Unemployment Rate Jersey, The Isle of Man And The Cayman Islands Jersey, The Isle of Man And The Cayman Islands [Member] Jersey, The Isle of Man And The Cayman Islands Gross amount of other items offset in the balance sheet Gross Financial Instruments Set Off Against Financial Instruments Subject To Offsetting Enforceable Master Netting Arrangements Or Similar Agreements, Other The amount of other financial instruments set off against other financial instruments when an entity: (a) currently has a legally enforceable right to set off the recognised amounts; and (b) intends either to settle on a net basis or to realise the asset and settle the liability simultaneously. asset/liability and settle the liability/asset simultaneously. TOTAL FINANCIAL ASSETS Total Financial Assets Remaining The total remaining financial assets including financial assets held for trading, financial assets designated at fair value through profit or loss, financial assets available for sale equity instruments, hedging derivatives and changes in the fair value of hedged items in portfolio hedges of interest rate risk. Loss component Loss component [member] Condensed consolidated statements of cash flows Statement of cash flows [abstract] Former senior managing directors Former Senior Managing Directors [Member] This member represents former Managing Directors. Type of measurement of expected credit losses [axis] Type of measurement of expected credit losses [axis] Coming from Securities services Brokerage fee income Shares owned by third parties received as security, percentage of share capital Shares Owned By Third Parties Received As Security, As Percentage Of Total Share Capital The percentage of shares owned by third parties and received as security in relation to total share capital. Other land Land Loans, Other [Member] This member stands for loans for other than developed consolidated land. Banco Santander Brasil Sa Subsidiary Banco Santander Brasil Sa Subsidiary [Member] Represents information pertaining to Banco Santander (Brasil) S.A., a subsidiary of the entity. Central banks and Credit institutions Central banks and Credit institutions Central Banks And Credit Institutions [Member] This member represents central banks and credit institutions. Santander Caceis Latam Holding 1, S.L Santander CACEIS Latam Holding 1, S.L. [Member] Santander CACEIS Latam Holding 1, S.L. By the effect of application of the various tax rates applicable in each country Tax effect of foreign tax rates PagoNxt PagoNxt [Member] PagoNxt Percentage of capital released of sale of Poland Share Buyback Program, Percentage Of Capital Released Of Sale Of Poland Share Buyback Program, Percentage Of Capital Released Of Sale Of Poland Other Staff costs Other employee expense SC Auto SC Auto [Member] SC Auto [Member] Changes in the fair value of financial liabilities at fair value through profit or loss attributable to changes in credit risk Other comprehensive income, before tax, change in fair value of financial liability attributable to change in credit risk of liability Increases (decreases) due to business combinations Change of perimeter Increase (decrease) through acquisition of subsidiary, equity Volatility Option Model Valuation Technique Volatility Option Model Valuation Technique [Member] Volatility Option Model Valuation Technique Caceis (Notes 3 and 12) Santander Bank Polska S.A. (Note 3) Caceis [Member] Caceis [Member] Other general administrative expenses Other general administrative expenses Other General Administrative Expenses Other General Administrative Expenses Credit spread Credit Spread Risk [Member] This member stands for a component of other price risk that represents the type of risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in the credit spread. Credit exposure percentage Credit Exposure Percentage The percentage of amount to total that is in exposure to loss resulting from credit risk. Schedule of number of employees with disabilities Disclosure Of Number Of Employees With Disabilities [Table Text Block] Tabular disclosure of number of employees with disabilities. Deferred conditional variable remuneration plan and linked to objectives (2024) Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2024 [Member] Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2024 Domestic Equity Instruments, Domestic [Member] This member stands for equity instruments that are issued by domestic companies. INVESTMENTS Balance at beginning of year Balance at end of year Investments Investments accounted for using equity method Purchases, fair value measurement, liabilities Purchases, fair value measurement, liabilities Eligible instruments T2 Subordinated Liabilities, Preference Shares and Participating Securities, Tier Two Capital The amount of liabilities for preference shares and participating preference securities that are subordinate to other liabilities with respect to claims and included within Tier 2 Capital. Cash flow hedges Income tax relating to cash flow hedges included in other comprehensive income Off shore entities, branches Off Shore Entities, Branches [Member] Off Shore Entities, Branches Remuneration of directors approved by the board of directors Key Management Personnel Compensation, Board Approved Annual Amount The annual fixed amount of remuneration of directors approved by the board of directors. Includes annual emolument and attendance fees. Schedule of subordinated liabilities detail, by currency of issue Schedule Of Subordinated Liabilities, Details [Table Text Block] Tabular disclosure of information pertaining to subordinated liabilities including issue by currency, outstanding amount and interest rate. Temporary differences Temporary differences [member] Compensation sought in litigation claim Litigation Contingencies, Compensation Sought In Litigation Litigation Contingencies, Compensation Sought In Litigation Percentage of reasonably possible decrease in actuarial assumption Percentage of reasonably possible decrease in actuarial assumption Subordinated Financial Bills (TIER II) Subordinated Financial Bills (TIER II) [Member] Subordinated Financial Bills (TIER II) Income (expense) from participation in refinancing operations program Income (Expense) From Participation In Refinancing Operations Program Income (Expense) From Participation In Refinancing Operations Program Consolidated LCR ratio (%) Consolidated Liquidity Coverage Ratio Consolidated Liquidity Coverage Ratio Annual salary increase rate Actuarial assumption of expected rates of salary increases Disclosure of debt instruments by issuer rating Disclosure Of Debt Instruments By Issuer Rating [Table Text Block] Disclosure Of Debt Instruments By Issuer Rating Deferred Conditional Variable Remuneration Plan Fourteenth Cycle 2024 Deferred Conditional Variable Remuneration Plan Fourteenth Cycle 2024 [Member] Deferred Conditional Variable Remuneration Plan Fourteenth Cycle 2024 Classes of contingent liabilities [domain] Classes of contingent liabilities [domain] Investments Purchase of interests in investments accounted for using equity method Net changes on financial assets Net Changes On Financial Assets The increase (decrease) in financial assets from other than transfers, write-offs and exchange differences, during the period. Schedule of detail, by Group company, of non-controlling interests Disclosure Of Non-Controlling Interest Components Explanatory [Table Text Block] The disclosure of components of non-controlling Interest. Proceeds from changes in ownership interests in subsidiaries that do not result in loss of control Proceeds from changes in ownership interests in subsidiaries that do not result in loss of control Schedule summarising remuneration related to life and disability insurance Disclosure Of Transactions Between Related Parties, Remuneration, Life Insurance [Table Text Block] Tabular disclosure of remuneration between the entity and its related parties for life and disability insurance. Disclosure of other provisions [line items] Disclosure of other provisions [line items] Financial liabilities designated at fair value through profit or loss Adjustments for increase (decrease) in financial liabilities measured at fair value through profit or loss Expected shortfall Expected Shortfall Expected Shortfall Price risk Other price risk [member] Other comprehensive income Disclosure of analysis of other comprehensive income by item [text block] Average number of employees Average number of employees Borrowed securities Financial Liabilities Attributable To Borrowed Securities The amount of financial liabilities attributable to borrowed securities. Condensed Financial Statements, Captions [Line Items] Condensed Financial Statements, Captions [Line Items] Finance leases Finance Lease Loans [Member] This member stands for finance lease loans. Exposure and impairment losses Disclosure of external credit grades [line items] Leased out under an operating lease Property, plant and equipment subject to operating leases [member] EUR/COP Euro And Colombia Peso [Member] Euro And Colombia Peso Annual discount rate Actuarial assumption of discount rates Prepayments and accrued income Prepayments And Accrued Income The amount of prepayments and accrued income. [Refer: Prepayments; Accrued income] Cash outflows High-Quality Liquid Assets, Cash Outflow High-Quality Liquid Assets, Cash Outflow Hedging instruments (items not designated) Other Reserves, Other Comprehensive Income, Before Tax, Hedging Instruments Not Designated Other Reserves, Other Comprehensive Income, Before Tax, Hedging Instruments Not Designated 1 % depreciation of euro, effect on consolidated equity Increase In Consolidated Equity Due To Reasonably Possible Depreciation Of Entity's Functional Currency The estimated increase in consolidated equity that would have been caused by a depreciation of entity's functional currency that was reasonably possible at the end of the reporting period. Schedule of main categories of plan assets Disclosure Of Main Categories Of Defined Benefit Plan Assets [Table Text Block] Disclosure of main categories of plan assets. TSB Banking Group plc (TSB) TSB Banking Group plc (TSB) [Member] TSB Banking Group plc (TSB) Liabilities Liabilities, Related Party Transactions The amount of liabilities attributable to related party transactions. Cash paid, immediate Key Management Personnel Compensation, Cash Payment Immediate Remuneration The amount of Key Management Personnel Compensation Cash Payment Immediate Remuneration. Types of customers [domain] Types of customers [domain] Other financial assets and liabilities Other Financial Assets And Liabilities [Member] Other Financial Assets And Liabilities FINANCIAL ASSETS AT FAIR VALUE THROUGH OTHER COMPREHENSIVE INCOME Financial assets at fair value through other comprehensive income Balance at beginning of the year Balance at end of year Fair Value Financial assets at fair value through other comprehensive income Other administrative expenses Other Administrative Expenses Expenses the entity classifies as administrative. Beneficiaries with target total variable remuneration higher or equal to 2.7 million euros Beneficiaries With Target Total Variable Remuneration Higher Or Equal To 2.7 Million Euros [Member] Beneficiaries With Target Total Variable Remuneration Higher Or Equal To 2.7 Million Euros Subordinated liabilities Disclosure of subordinated liabilities [text block] Maturity of other financial instruments Maturity Of Other Financial Instruments Maturity Of Other Financial Instruments Changes in the fair value of equity instruments measured at fair value through other comprehensive income (hedged item) Other Comprehensive Income, Before Tax, Gains (Losses) On Hedged Item Other Comprehensive Income, Before Tax, Gains (Losses) On Hedged Item Changes in fair value recognized in profit or loss Gains (losses) recognised in profit or loss including exchange differences, fair value measurement, assets Gains or losses on non financial assets, net Disclosure Of Gains (Losses) On Disposal Of Assets Not Classified As Non-Current Assets Held For Sale [Text Block] The entire disclosure of gains (losses) on disposal of assets not classified as held for sale. From BB- to B- From BB- To B- [Member] From BB- To B- TAX LIABILITIES Tax liabilities Tax Liabilities The amount of tax for current, prior, and future periods to the extent unpaid. Schedule of provisional accounting statement for interim dividend Schedule Of Provisional Accounting Statement For Interim Dividend [Table Text Block] Schedule Of Provisional Accounting Statement For Interim Dividend Immediate payment percentage Variable Remuneration, Immediate Payment Percentage The percentage of variable remuneration with immediate payment during the period. Other provisions Other provisions Changes in goodwill Reconciliation of changes in goodwill [abstract] Disclosure of reserves within equity [line items] Disclosure of reserves within equity [line items] Significant unobservable input, liabilities Significant unobservable input, liabilities Webster Financial Corporation Webster Financial Corporation [Member] Webster Financial Corporation Cash-generating units [domain] Cash-generating units [domain] Disclosure of unconsolidated structured entities [line items] Disclosure of unconsolidated structured entities [line items] Number of persons Total number of employees Number of employees Fair value less costs to sell of non-current assets held for sale exceeding carrying amount Unrealized Gain (Loss) Of Fair Value Less Costs To Sell Of Non-Current Assets Held For Sale The net excess or deficiency of the fair value less costs to sell of non-current assets held for sale over or under carrying amount, which excess value or deficiency has not been recognized in earnings of the entity. Repaid By Banco Santander S.A. In September 2025 Repaid By Banco Santander S.A. In September 2025 [Member] Repaid By Banco Santander S.A. In September 2025 Deferred payment, short term, number of deferrals Variable Remuneration, Deferred Payment, Short Term, Number Of Deferrals Variable Remuneration, Deferred Payment, Short Term, Number Of Deferrals 1. Cash flows from operating activities Cash flows from (used in) operating activities [abstract] Brazilian real Brazil, Brazil Real Government debt Government Debt [Member] Government Debt Reportable Legal Entities Reportable Legal Entities [Member] Income from companies accounted for using the equity method Effect of equity accounting Investments accounted for using the equity method Share of profit (loss) of associates and joint ventures accounted for using equity method Options, futures and other derivatives Option Contract And Futures Contract And Other Derivatives [Member] The member stands for options, futures and other derivatives. Document Period End Date Document Period End Date Audit committee and risk supervision, regulation and compliance committee Audit Committee And Risk Supervision, Regulation And Compliance Oversight Committee [Member] This member represents members of the Audit Committee and Risk Supervision, Regulation and Compliance Oversight Committees. Schedule of detail of asset balances measured at fair value through profit or loss Disclosure Of Financial Assets At Fair Value Through Profit Or Loss [Table Text Block] Tabular disclosure of financial assets measured at fair value through profit or loss. Past service cost Past Service Cost Charged To Income Statement Related To Defined Benefits Past service cost charged to income statement related to defined benefits. Non-adjusting events after reporting period [domain] Non-adjusting events after reporting period [domain] Santander Towarzystwo Funduszy Inwestycyjnych S.A. And Santander Bank Polska S.A. Santander Towarzystwo Funduszy Inwestycyjnych S.A. And Santander Bank Polska S.A. [Member] Santander Towarzystwo Funduszy Inwestycyjnych S.A. and Santander Bank Polska S.A. Within 3 months Within 3 months Not later than three months [member] Financial liabilities at fair value through profit or loss Financial Liabilities At Fair Value Through Profit Or Loss And Financial Liabilities At Fair Value Through Profit Or Loss That Meet The Definition Of Held For Trading Financial Liabilities At Fair Value Through Profit Or Loss And Financial Liabilities At Fair Value Through Profit Or Loss That Meet The Definition Of Held For Trading Chair of the risk supervision, regulation and compliance committee Risk Supervision Regulation And Compliance Oversight Committee, Chairman [Member] This member stands for the person serving as chairman of the risk supervision, regulation and compliance oversight committee of the board of directors. Intangible assets - Goodwill Disclosure of goodwill [text block] Other collections/payments related to financing activities Other inflows (outflows) of cash, classified as financing activities Investments Proceeds from sales of investments accounted for using equity method Valuation adjustments Other Reserves, Valuation Adjustments A component of equity representing reserves for items not reclassified through profit or loss and items that may be reclassified to profit or loss. Other collateral received Other Collateral Assets [Member] This member stands for other collateral assets received. Excludes credits and loans, equity instruments, debt securities, and own debt securities issued other than own covered bonds or ABS. Other Other Contingent Commitments [Member] Other contingent commitments. Unrealized gains (losses) on fair value adjustment Unrealized Gains (Losses) On Fair Value Adjustment Unrealized Gains (Losses) On Fair Value Adjustment Transfer to Assets held for sale (Notes 3 y 12) Decrease Through Classified As Held For Sale Or Changes In Scope Of Consolidation, Goodwill The decrease in goodwill due to classification as held for sale or changes in scope of consolidation. Classes of financial instruments [axis] Classes of financial instruments [axis] Financial guarantees Bank Sureties Granted [Member] Information pertaining to bank sureties granted. Arbitration matter, amount claimed by entity Arbitration Matter, Amount Claimed By Entity The amount claimed by the entity in the arbitration matter. Pensionable base, expressed as a percent of fixed, bonus average Defined Benefit Obligation, Pensionable Base, Basis, Percentage Of Bonus Average Defined Benefit Obligation, Pensionable Base, Basis, Percentage Of Bonus Average Number of employees - men Number Of Men Employees The number of personnel, identified as men, employed by the entity at a date. Impairment losses reversed with a credit to income Reversal of impairment loss recognised in profit or loss Impairment losses reversed with a credit to profit or loss Reversal of impairment loss recognised in profit or loss Product and Service [Axis] Product and Service [Axis] Schedule of leverage capital and ratios Schedule Of Leverage Capital And Ratio [Table Text Block] Tabular disclosure for leverage capital and ratios. Classes of financial assets [axis] Classes of financial assets [axis] Black Scholes model Black Scholes Model [Member] Black Scholes Model Brand names Brand names [member] Disclosure of expected rate of return assumptions Disclosure Of Expected Rate Of Return Assumptions [Table Text Block] Disclosure of expected rate of return assumptions. Deposits redeemable at notice Deposits Redeemable At Notice [Member] Deposits Redeemable At Notice Total Costs Total Cost, Segment Reporting Total Cost, Segment Reporting Bank subsidiaries Bank Subsidiaries [Member] Information pertaining to subsidiaries of the parent that are banks. Cash flow hedges (effective portion) Hedging derivatives. Cash flow hedges (Effective portion) Reserve of cash flow hedges Statistical Measurement [Axis] Statistical Measurement [Axis] Land Land [member] Others Other Financial Assets [Member] This member stands for other financial assets. Transfer from equity to liabilities Transfer From Equity To Liabilities Transfer From Equity To Liabilities Others Miscellaneous Other Reserves A component of other reserves within equity representing reserves not otherwise specified. Classes of assets [axis] Classes of assets [axis] Banco Santander, S.A., May 2021 Issuance By Banco Santander S.A. In May 2021, Series In Euros [Member] Issuance By Banco Santander S.A. In May 2021, Series In Euros Operating segment Operating segments [member] Treasury shares, held by the group, as a percentage of issued share capital (in percentage) Treasury Shares, Held By The Group, Percentage Of Issued Share Capital Treasury Shares, Held By The Group, Percentage Of Issued Share Capital 2030 Later than four years and not later than five years [member] Rest of the Group Rest Of The Group [Member] Rest Of The Group Disclosure of reconciliation of changes in goodwill [table] Disclosure of reconciliation of changes in goodwill [table] Changes in the fair value of debt instruments through other comprehensive income Income tax relating to financial assets measured at fair value through other comprehensive income included in other comprehensive income Number of shares outstanding, entitled to receive dividend Number Of Shares Outstanding, Entitled To Receive Dividend Number Of Shares Outstanding, Entitled To Receive Dividend Housing price change Estimation Of Expected Losses, Housing Price Change Rate Represents the housing price change rate percentage in the estimation of expected credit losses. International Equity Instruments, International [Member] This member stands for equity instruments that are issued by international companies. Stellantis Financial Services Italia S.p.A. Stellantis Financial Services Italia S.p.A. [Member] Stellantis Financial Services Italia S.p.A. IR Options IR Options [Member] IR Options Earnings/(losses) per share Earnings per share [abstract] Subordinated issue, notional amount, placed on the market Notional Amount, Placed On The Market Notional Amount, Placed On The Market Range [axis] Range [axis] Currently stated [member] Currently stated [member] G-SIB designation, number of criteria Global Systemically Important Bank Designation, Number of Criteria Number of criteria used to determine designation as global systemically important bank. Fixed rate debt Fixed rate Fixed interest rate [member] C) Cash flows from financing activities Cash flows from (used in) financing activities, discontinued operations Deposit insured with deposit guarantee systems, retail deposits (in percentage) Deposit Insured With Deposit Guarantee Systems, Retail Deposits, Percentage Deposit Insured With Deposit Guarantee Systems, Retail Deposits, Percentage Deposits from customers [abstract] Deposits from customers [abstract] CET objective, result Variable Remuneration, Deferred Payment, CET1 Objective, Result Variable Remuneration, Deferred Payment, CET1 Objective, Result Operating profit/(loss) before tax Profit before taxes From continuing operations Profit (loss) before tax Margin of a reference portfolio Margin Of A Preference Portfolio, Measurement Input [Member] Margin Of A Preference Portfolio, Measurement Input Issuance by Banco Santander S.A. in September 2017 Issuance By Banco Santander S.A. In September 2017 [Member] This member stands for issuance by Banco Santander S.a. in September 2017. Subsidiaries and other business units Cash flows from losing control of subsidiaries or other businesses, classified as investing activities Reserves Capital reserve Other reclassifications Other Reclassification Adjustments, Reserve Of Hedging Instruments Other Reclassification Adjustments, Reserve Of Hedging Instruments Legal Case Related To Tax Compensation With Credits Legal Case Related To Tax Compensation With Credits [Member] Legal Case Related To Tax Compensation With Credits Large exposure threshold percentage Large Exposure, Percentage Of Eligible Capital Threshold Threshold percentage for "Large Exposures" as defined by CRR (Regulation (EU) No 575/2013). "Large Exposures" are defined as exposures from a customer or group of connected customers that equals or exceeds 10% of the entity's eligible capital. Loan To Value [Axis] Loan To Value1 [Axis] Information by loan-to-value (LTV) ratio, for example, but not limited to, 80% to 100%. Element name and standard label in LTV [numeric lower end] to [numeric higher end] Percent [Member] or LTV Greater Than [low end numeric value] Percent [Member] or LTV Less Than [high end numeric value] Percent [Member] formats. Santander Spain Santander Spain [Member] Santander Spain Types of Assets [Axis] Types Of Assets [Axis] The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table. Hyundai Capital UK Limited Hyundai Capital UK Limited [Member] Hyundai Capital UK Limited Consolidated statement of cash flows Description of accounting policy for cash flows [text block] Percentage increase (decrease) in lending Increase (Decrease) In Lending, Percentage Increase (Decrease) In Lending, Percentage Future interest rate Futures contract [member] Additional Tier 1 Financial Notes Additional Tier 1 Financial Notes [Member] Additional Tier 1 Financial Notes Disclosure of other provisions [table] Disclosure of other provisions [table] 2024 variable remuneration Share Based Variable Remuneration Award 2024 [Member] Share Based Variable Remuneration Award 2024 Issuance of preferred shares Issuance Of Preferred Shares Issuance Of Preferred Shares Issuance By Santander Bank Polska S.A. In August 2010 Issuance By Santander Bank Polska S.A. In August 2010 [Member] Issuance By Santander Bank Polska S.A. In August 2010 Number of markets with OpenBank Deferred Variable Remuneration, Milestone, Migration Of OpenBank And Launch, Number Of Markets Deferred Variable Remuneration, Milestone, Migration Of OpenBank And Launch, Number Of Markets Classes of financial instruments [domain] Classes of financial instruments [domain] Disclosure of detailed information about business combination [table] Disclosure of detailed information about business combination [table] Non-local sovereign cross border risk Non Local Sovereign Cross Border Risk [Member] This member stands for non-local sovereign cross border risk. Share buyback program, percentage of underlying profit Share Buyback Program, Percentage Of Underlying Profit Share Buyback Program, Percentage Of Underlying Profit Office and IT equipment Office And Computer Equipment [Member] This member stands for a class of property, plant and equipment representing equipment used to support office functions, not specifically used in the production process and computer equipment. Acquisition for the year (net) Increase (decrease) through business combinations, deferred tax liability (asset) From AAA to AA- From AAA to AA- [Member] From AAA to AA- Interest received Interest received, classified as operating activities Capital reduction Reduction of issued capital Reduction of issued capital Other units Other Geographical Units [Member] This member stands for other geographical units. Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name Insurance contracts [domain] Insurance contracts [domain] CASH AND CASH EQUIVALENTS AT BEGINNING OF THE YEAR CASH AND CASH EQUIVALENTS AT END OF THE YEAR Cash and cash equivalents if different from statement of financial position Products and services [domain] Products and services [domain] Other similar obligations Other Similar Benefits Plans [Member] This member stands for other similar benefits plans other than post-employment plans. Schedule of condensed balance sheets and condensed underlying income statements by primary and secondary segments Disclosure of operating segments [text block] Legal Case Relating To Tax Deductibility Of Sale Of Shares Legal Case Relating To Tax Deductibility Of Sale Of Shares [Member] Legal Case Relating To Tax Deductibility Of Sale Of Shares Schedule of deferred tax assets and liabilities Disclosure of temporary difference, unused tax losses and unused tax credits [text block] Subordinated issue, UK government bond term Subordinated Issue, UK Government Bond Term Subordinated Issue, UK Government Bond Term Impairment losses Impairment loss recognised in profit or loss, goodwill Impairment loss recognised in profit or loss, goodwill Disclosure of detailed information about intangible assets [table] Disclosure of detailed information about intangible assets [table] OTHER RESERVES Other reserves Total debt Borrowings Reserves Capital Reserve Common Equity Tier One Basis The amount of capital reserves required for computation of Common Equity Tier I (CET I) equity. Disclosure of detailed information about goodwill Disclosure Of Detailed Information About Goodwill [Table Text Block] Disclosure Of Detailed Information About Goodwill CZK/EUR Czech Republic, Koruny And Euro [Member] Czech Republic, Koruny And Euro Loan commitments granted Loans and credits Loan commitments [member] Net changes of the exposure and modifications in the credit risk Increase (decrease) through changes in models or risk parameters, financial assets Major customers [domain] Major customers [domain] Impairment charge for the year Impairment loss recognised in profit or loss, property, plant and equipment Financial instruments purchased credit impaired Financial instruments purchased or originated credit-impaired [member] Factoring accounts payable Factoring Accounts Payable The amount of factoring accounts payable. Caceis Bank Caceis Bank [Member] Caceis Bank CASH FLOWS FROM FINANCING ACTIVITIES Cash flows from (used in) financing activities Other land Undeveloped Land Collateral [Member] This member stands for collateral in the form of undeveloped land. Optimistic scenario  Optimistic Scenario [Member] Represents information pertaining to Optimistic scenario. Santander Consumer S.A. Santander Consumer S.A. [Member] Santander Consumer S.A. Deferred conditional variable remuneration plan fourth cycle Deferred Conditional Variable Remuneration Plan Fourth Cycle 2014 [Member] Information pertaining to the Deferred Conditional Variable Remuneration Plan Fourth Cycle (2014). Notional amount, placed on the market (in percentage) Notional Amount, Placed On The Market, Percentage Notional Amount, Placed On The Market, Percentage Gain (loss) on sale (Note 12) Gains (losses) on disposals of non-current assets Expected return on insurance contracts linked to pensions Expected return on insurance contracts linked to pensions Expected Return On Insurance Contracts Linked To Pensions Expected return on insurance contracts linked to pensions. Shares delivered (deferred payment variable remuneration) (in shares) Number of shares delivered (in shares) Number Of Shares Earned In Share-Based Payment Arrangement, Deferred Variable The number of shares earned for a deferred variable share-based payment arrangement. Deferred payment, sustainability objective, number of metrics Variable Remuneration, Deferred Payment, Sustainability Objective, Number Of Metrics Variable Remuneration, Deferred Payment, Sustainability Objective, Number Of Metrics Change in provision assuming 100bp increase in Manheim index (as a percent) Percent Change In Provision Assuming 100 Basis Point Increase In Manheim Index Percent Change In Provision Assuming 100 Basis Point Increase In Manheim Index Effect of reassessment of deferred taxes Tax Effect Of Remeasurement Of Deferred Tax The amount that represents the difference between the tax expense (income) and the product of the accounting profit multiplied by the applicable tax rate(s) that relates to remeasurement of deferred taxes. Revaluation gains Reserve Of Gains On Remeasuring Financial Assets At Fair Value With Changes In Other Comprehensive Income A component of equity representing accumulated gains on remeasuring available-for-sale financial assets. Less - Fair value of plan assets Fair value of plan assets Plan assets, at fair value (-) OWN SHARES Treasury shares Treasury shares Staff costs (note 46) Increase Through Defined Benefit Pension Plans Personnel Expense, Provisions Additions to provisions for defined benefit pension plans for personnel expenses. Increase (decrease) in provision for loan loss Increase (Decrease) In Provision For Loan Loss Increase (Decrease) In Provision For Loan Loss Percent awarded in options over shares Key Management Personnel Compensation, Long Term And Deferred Compensation, Percent Of Total Awarded In Options Over Shares Key Management Personnel Compensation, Long Term And Deferred Compensation, Percent Of Total Awarded In Options Over Shares Santander Consumer Nordics Santander Consumer Nordics [Member] Santander Consumer Nordics Profit/(loss) attributable to the parent, increase (decrease) in constant euros Profit Loss Attributable To Owners Of Parent, Increase (Decrease), Percentage, In Constant Euros Profit Loss Attributable To Owners Of Parent, Increase (Decrease), Percentage, In Constant Euros Statement of changes in equity [table] Statement of changes in equity [table] Actuarial assumptions [axis] Actuarial assumptions [axis] Rest of Europe Europe Excluding Spain [Member] Continent of Europe excluding Spain. Deferred conditional variable remuneration plan fifth cycle Deferred Conditional Variable Remuneration Plan Fifth Cycle 2015 [Member] Information pertaining to the Deferred Conditional Variable Remuneration Plan Fifth Cycle (2015). EQ option pricing model EQ Option Pricing Model Valuation Technique [Member] EQ Option Pricing Model Valuation Technique Loans and advances, customers Interest income on loans and advances to customers Volatility Historical volatility for shares, measurement input [member] Law 38/2022, Tax Reform Law 38/2022, Tax Reform [Member] Law 38/2022, Tax Reform Securities and commodities derivatives and other Securities And Commodities Derivatives And Other [Member] This member stands for securities and commodities derivatives and other. Deferred payment, long term, percentage paid in cash Variable Remuneration, Deferred Payment, Long Term, Percentage Paid In Cash Variable Remuneration, Deferred Payment, Long Term, Percentage Paid In Cash Classes of assets [domain] Classes of assets [domain] Gains/losses on financial assets and liabilities, net Gains Losses On Financial Assets And Liabilities Net Net amount of gains or losses on financial assets and liabilities, net. Issuance By Banco Santander S.A. In November 2025 Issuance By Banco Santander S.A. In November 2025 [Member] Issuance By Banco Santander S.A. In November 2025 Tangible assets Proceeds from sales of property, plant and equipment, classified as investing activities Debt instruments Interest income on debt instruments held Types of hedges [domain] Types of hedges [domain] Marketable assets Level 1 Marketable Assets Level 1 [Member] Marketable Assets Level 1 Chase Nominees Limited Chase Nominees Ltd [Member] Represents information pertaining to Chase Nominees Ltd.. Banco Santander Brazil SA Subsidiary Banco Santander Brazil SA Subsidiary [Member] Represents information pertaining to Banco Santander (Brasil) S.A., a subsidiary of the entity. Interest rate Estimation Of Expected Losses, Interest Rate Represents the interest rate percentage in the estimation of expected credit losses. Customers Customer deposits Financial liabilities: customers Deposits Customers [Member] This member represents amounts held on account by the entity for customers, including money market operations through central counterparties. Excludes deposits at central banks and credit institutions. Disclosure Of Accounting Policies Abstract [Abstract] Disclosure Of Accounting Policies [Abstract] Disclosure Of Accounting Policies Abstract [Abstract] Minimum Min Bottom of range [member] Transferred to initial carrying amount of hedged items Amounts Transferred To Initial Carrying Amount Of Hedged Items, Before Tax Amounts Transferred To Initial Carrying Amount Of Hedged Items, Before Tax Equity swap Equity Swap Contract [Member] Equity Swap Contract Chairman Board of Directors Chairman [Member] Categories of related parties [axis] Categories of related parties [axis] Number of share buyback programs Number Of Share Buyback Programs Number Of Share Buyback Programs Audit-related services Auditors Remuneration For Audit Related Services The amount of fees paid or payable to the entity's auditors for audit related services. Tangible assets Impairment Loss Or Reversal Of Impairment Recognised In Profit Or Loss, Tangible Assets Net amount of impairment loss or reversal of impairment recognized in profit or loss on tangible assets. Profit/(loss) for the year CONSOLIDATED PROFIT/(LOSS) FOR THE YEAR Profit or loss for the year Total profit Profit (loss) Spanish government debt securities Spanish Government Debt Securities [Member] This member stands for debt securities issued by the domicile country government. Share-based compensation arrangement, maximum authorized Amount Share-Based Compensation Arrangement, Maximum Authorized Amount Share-Based Compensation Arrangement, Maximum Authorized Amount Other companies Aggregate cash-generating units for which amount of goodwill or intangible assets with indefinite useful lives is not significant [member] Mortgage loans, adjustment to gross carrying amount Mortgage Loans, Denominated In/Indexed To Swiss Francs, Adjustment To Gross Carrying Amount Mortgage Loans, Denominated In/Indexed To Swiss Francs, Adjustment To Gross Carrying Amount Rest Eurozone Rest Of Eurozone [Member] This member stands for countries in the rest of the eurozone (monetary union of the European Union member states which have adopted the euro as their primary currency). Excludes Spain, Portugal, Italy, Greece, Ireland, and the United Kingdom. (Charge)/Credit to asset and liability valuation adjustments Deferred Tax Relating To Items Charged (Credited) Directly To Liability Valuation Adjustments The amount of deferred tax related to items charged to liability valuation adjustments. Non current liabilities Non-current liabilities Digital Transformation Award 2020 & 2021 Digital Transformation Award 2020 & 2021 [Member] Digital Transformation Award 2020 & 2021 Closing foreign exchange rate Exchange rate Closing foreign exchange rate Price Based Valuation Technique Price Based Valuation Technique [Member] Price Based Valuation Technique Additions / disposals (net) due to change in the scope of consolidation Net Of Additions And Disposals To Property Plant And Equipment Due To Change In Scope Of Consolidation The net amount of additions and disposals to property, plant and equipment due to change in scope of consolidation. Other warehouses Other Warehouses [Member] This member represents other warehouses. Sol Daurella Sol Daurella Sol Daurella Comadran [Member] The member that represents an individual key personnel named Sol Daurella Comadran. Primary and secondary segments reporting Disclosure of entity's operating segments [text block] High-quality liquid assets-HQLAs High-Quality Liquid Assets High-Quality Liquid Assets Deposits from central banks at amortised cost due to participation in the refinancing operations program Deposits From Central Banks At Amortised Cost Due To Participation In Refinancing Operations Program Represents the deposits from central banks at amortised cost due to participation in refinancing operations program. Dividends per share (in eur per share) Dividends recognised as distributions to owners per share Disclosure of concentrations by risk factor Disclosure Of Nature And Extent Of Risks By Risk Factor [Text Block] The disclosure of information that enables users of financial statements to evaluate the nature and extent of risks, by risk factor, to which the entity is exposed. Discount curve Discount Curve, Measurement Input [Member] Discount Curve, Measurement Input Banco Santander, S.A., May 2024 Issuance By Banco Santander S.A. In May 2024 [Member] Issuance By Banco Santander S.A. In May 2024 Total for all associates Total for all associates [member] Issuance by Banco Santander S.A. in November 2021 Issuance By Banco Santander S.A. In November 2021 [Member] Issuance By Banco Santander S.A. In November 2021 Liability for Remaining Coverage (LRC) Net Liabilities Or Assets For Remaining Coverage [Member] Net Liabilities Or Assets For Remaining Coverage Less, bank overdrafts refundable on demand Bank overdrafts Reclassification no-current asset held for sale Increase (Decrease) Through Classified As Held For Sale, Deferred Tax Liability Increase (Decrease) Through Classified As Held For Sale, Deferred Tax Liability Remuneration of PPCC and PPCA Adjustment To Profit (Loss) For Remuneration Of Contingently Convertible Preferred Securities Adjustment To Profit (Loss) For Remuneration Of Contingently Convertible Preferred Securities Written-off assets Financial assets written off during reporting period and still subject to enforcement activity, contractual amount outstanding Disclosure of contingent liabilities [table] Disclosure of contingent liabilities [table] Present value of defined benefit obligation Present value of defined benefit obligation [member] Accounting for leases Description of accounting policy for leases [text block] (-) Interim dividends Interim Dividends [Member] This member stands for the portion of equity related to dividends and remuneration. Assets and liabilities not classified as held for sale Assets and liabilities not classified as held for sale [member] Retained earnings [abstract] Burden income Estimation Of Expected Losses, Burden Income Rate Estimation Of Expected Losses, Burden Income Rate Coming from Securities services Fee And Commission Income, Securities Services [Abstract] n/a. Reclassification adjustments on exchange differences on translation of foreign operations, net of tax Reclassification adjustments on exchange differences on translation of foreign operations, net of tax Fee and commission income [abstract] Fee and commission income [abstract] Analysis of income and expense [abstract] (Charge)/Credit to asset and liability valuation adjustments Deferred Tax Relating To Items Charged or Credited Directly To Asset and Liability Valuation Adjustments The amount of deferred tax related to items credited (charged) to asset and liability valuation adjustments. Other Non-Monetizable Tax Assets [Member] This member stands for deferred tax assets that must be deducted from regulatory capital. Marketable assets Level 2A Marketable Assets Level 2A [Member] Marketable Assets Level 2A Pound sterling GBP United Kingdom, Pounds Prepayment modelling Prepayment Modeling Valuation Technique [Member] Prepayment Modeling Valuation Technique Deferred payment, short term, percentage paid in cash Variable Remuneration, Deferred Payment, Short Term, Percentage Paid In Cash Variable Remuneration, Deferred Payment, Short Term, Percentage Paid In Cash LIABILITIES Liabilities FINANCIAL LIABILITIES Liabilities [abstract] Number of categories of encumbered assets Collateral Assets, Number Of Categories Number of categories of encumbered assets. Amortisation of other equity instruments Amortisation Of Other Equity Instruments Amortisation Of Other Equity Instruments Repaid By Banco Santander S.A. In August 2025, ISIN XS1384064587 Repaid By Banco Santander S.A. In August 2025, ISIN XS1384064587 [Member] Repaid By Banco Santander S.A. In August 2025, ISIN XS1384064587 Deferred variable compensation, third, fourth and fifth portion Deferred Variable Compensation, Third, Fourth And Fifth Portion [Member] Deferred Variable Compensation, Third, Fourth And Fifth Portion Provisions [abstract] Provisions [abstract] Carrying amount Carrying amount [member] Chair of the remuneration committee Remuneration Committee, Chairman [Member] This member stands for the person serving as chairman of the remuneration committee of the board of directors. Members of the appointments committee Nomination committee Appointments Committee [Member] This member stands for those persons serving as members of the appointments committee of the board of directors. Unobservable inputs [domain] Unobservable inputs [domain] Carrying amount of hedged items - Liabilities Hedged item, liabilities Deferred variable in instruments Key Management Personnel Compensation, Deferred Share-Based Short-Term Employee Benefits The amount of deferred share-based compensation to key management personnel in the form of short-term employee benefits. LIABILITIES UNDER INSURANCE CONTRACTS Liabilities under insurance contracts Liabilities under insurance contracts Insurance contracts issued that are liabilities Base scenario Base Scenario [Member] Represents information pertaining to base scenario. Insurance contracts by components [axis] Insurance contracts by components [axis] Securities underwriting and placement Brokerage Fee Income Securities Underwriting And Placement The amount of income recognised for brokerage fees charged by the entity from underwriting and placement of securities. Balances held under the welfare system Key Management Personnel Compensation, Defined Contribution Plan, Balances Held The balances held by key management personnel in defined contribution plan. Schedule of short positions Disclosure Of Short Positions [Table Text Block] Tabular disclosure of short positions (liabilities). Financial assets at fair value through other comprehensive income Investments in equity instruments designated at fair value through other comprehensive income Sensitivity analysis, discount rate adjustment, decrease (in basis points) Sensitivity Analysis, Discount Rate Adjustment, Decrease Sensitivity Analysis, Discount Rate Adjustment, Decrease Change in average foreign currency exchange rate (as a percent) Foreign Currency Exchange Rate, Change In Average Rate, As A Percent The percentage change in the average foreign currency exchange rate. Disposal of own equity instruments Proceeds from sale or issue of treasury shares Memorandum items Memorandum Items Memorandum Items Change in provision assuming 100bp decrease in GDP growth rate (as a percent) Percent Change In Provision Assuming 100 Basis Point Decrease In GDP Growth Rate Percent Change In Provision Assuming 100 Basis Point Decrease In GDP Growth Rate Lending, credit risk percentage of group Lending, Credit Risk Percentage Of Group Lending, Credit Risk Percentage Of Group Schedule of evolution projection based on main macroeconomic indicators Disclosure Of Macroeconomic Scenarios [Table Text Block] The tabular disclosure of macroeconomic scenarios. Sales of insurance and funds Commissions On Sales Of Insurance And Funds Expense recognised for commissions incurred on sales of insurance and funds during the period. Inefficiency of fair value hedges of equity instruments measured at fair value with changes in other comprehensive income Hedge Ineffectiveness Measured At Fair Value Through Other Comprehensive Income Hedge Ineffectiveness Measured At Fair Value Through Other Comprehensive Income Ebury Partners Ltd Ebury Partners Ltd [Member] Ebury Partners Ltd 2023 variable remuneration Share Based Variable Remuneration Award 2023 [Member] Share Based Variable Remuneration Award 2023 Net assets Assets (liabilities) Internal Models (level 2 and 3) Level 2 and 3 of fair value hierarchy [member] Subordinated issue, UST rate term Subordinated Issue, UST Rate Term Subordinated Issue, UST Rate Term Other financial liabilities Disclosure Of Other Financial Liabilities [Text Block] The disclosure of other financial liabilities. Others Impairment Loss Or Reversal Of Impairment Recognised In Profit Or Loss Other Non-Financial Assets, Net Net amount of impairment or reversal of impairment recognised in profit or loss on other non-financial assets. Disclosure of liquidity coverage ratio by component Disclosure Of Liquidity Coverage Ratio By Component [Table Text Block] Disclosure Of Liquidity Coverage Ratio By Component Issuance by Banco Santander S.A. in November 2023 Issuance By Banco Santander S.A. In November 2023 [Member] Issuance By Banco Santander S.A. In November 2023 Additions Additional recognition, goodwill Derivative financial instruments Derivative Financial Instruments Related Party Transactions The derivative financial instruments resulting from related party transactions. Private fixed income Private Fixed Income Debt Securities [Member] Private Fixed Income Debt Securities. Banco Santander, S.A., July 2025 Issuance By Banco Santander S.A. In July 2025 [Member] Issuance By Banco Santander S.A. In July 2025 Financial assets, at fair value Assets at beginning of period Assets at end of period Financial assets, at fair value Statistical Measurement [Domain] Statistical Measurement [Domain] Collateral [Domain] Collateral1 [Domain] Collateral1 Assets under insurance or reinsurance contracts and Liabilities under insurance or reinsurance contracts Description of accounting policy for reinsurance [text block] Actuarial gains and losses on defined benefit pension plans Reserve of remeasurements of defined benefit plans Increase (decrease) in residential mortgage credit risk (in percentage) Increase (Decrease) In Residential Mortgage Credit Risk, Percentage Increase (Decrease) In Residential Mortgage Credit Risk, Percentage 2025 And 2026 Program 2025 And 2026 Program [Member] 2025 And 2026 Program Current service cost Increase in net defined benefit liability (asset) resulting from current service cost Other Other Increase (Decrease) In Fair Value Measurement, Assets The increase (decrease) in the fair value measurement of assets that the entity does not separately disclose in the same statement or note. Impairment or reversal of impairment on non-financial assets, net Impairment Loss Reversal Of Impairment Recognised In Profit Or Loss Non-Financial Assets, Net Net amount of impairment loss and reversal of impairment recognised in profit or loss on non-financial assets. Subordinated issue, initial interest rate term Subordinated Issue, Initial Interest Rate Term The initial interest rate term of the subordinated issue. Subordinated liabilities, preferred securities Subordinated Liabilities, Preferred Securities [Member] Preferred securities classified as subordinated liabilities. NOK/EUR Norway, Krone And Euro [Member] Norway, Krone And Euro Useful life measured as period of time, intangible assets other than goodwill Useful life measured as period of time, intangible assets other than goodwill Change in provision assuming 100bp increase in housing price change rate (as a percent) Percent Change In Provision Assuming 100 Basis Point Increase In Housing Price Change Rate Percent Change In Provision Assuming 100 Basis Point Increase In Housing Price Change Rate Options exercised (in shares) Number of share options exercised in share-based payment arrangement Santander Investment, S.A. Santander Investment SA [Member] Represents information pertaining to Santander Investment, S.A., a subsidiary of the entity. Pensionable base, expressed as a percent of fixed, percentage Defined Benefit Obligation, Pensionable Base, Percentage Of Basis Defined Benefit Obligation, Pensionable Base, Percentage Of Basis Remuneration and other benefits paid to the Bank's directors and senior managers Remuneration And Other Benefits Paid To The Bank's Directors And Senior Managers [Abstract] No definition available. Insurance contracts linked to pensions Insurance contracts that are assets Insurance contracts issued that are assets Schedule of on and off-balance sheet assets provided as security in transactions to obtain liquidity Disclosure of how entity manages liquidity risk [text block] Unrecognised, deferred tax liabilities Unrecognised, Deferred Tax Liabilities, Taxation That Would Arise From Undistributed Earnings Unrecognised, Deferred Tax Liabilities, Taxation That Would Arise From Undistributed Earnings Schedule of off-balance sheet funds managed by the entity and joint ventures Schedule Of Off Balance Sheet Funds [Table Text Block] Schedule of off-balance sheet funds managed by the entity and joint ventures. Net incorporation of companies into the Group Net incorporation of companies into the Group Increase (decrease) in net defined benefit liability (asset) resulting from business combinations and disposals Interest expense Finance Cost, Related Party Transactions The amount of finance costs incurred by the entity in related party transactions. Contribution to insurance policies Post Employment Benefit Expense Contribution To Insurance Policies The amount of post-employment benefit expense relating to contribution to insurance policies. Share of other recognised income and expense of investments Share of other comprehensive income of associates and joint ventures accounted for using equity method that will be reclassified to profit or loss, net of tax OTHER EQUITY Other equity interest Other equity interest Minority interests Non-Controlling Interests Common Equity Tier One Basis The amount of non-controlling interests required for computation of Common Equity Tier 1 (CET I) equity. Closing foreign exchange rate, applied, hyperinflationary economy Closing Foreign Exchange Rate, Applied, Hyperinflationary Economy Closing Foreign Exchange Rate, Applied, Hyperinflationary Economy Goodwill and intangible assets Regulatory Capital, Adjustment To Remove Intangible Assets And Goodwill ln calculation of regulatory capital, the adjustment to remove the applicable amount of intangible assets and goodwill as provided in the regulations. Unemployment rate Estimation Of Expected Losses, Unemployment Rate Represents the unemployment rate percentage in the estimation of expected credit losses. Net operating income Net Operating Income (Expense), Segment Reporting Net Operating Income (Expense), Segment Reporting Other interest Interest Income On Financial Assets Other Than Loans And Advances And Debt Instruments The amount of interest income on financial assets other than loans and advances and debt instruments. Transactions in transit Other receivables Administrative expenses, depreciation and amortisation Administrative Expenses, Depreciation And Amortisation The amount of administrative expense and depreciation. Other recognised income and expense of investments in subsidiaries, joint ventures and associates Share of other comprehensive income of associates and joint ventures accounted for using equity method that will not be reclassified to profit or loss, net of tax Gain or losses on non-financial assets and investments, net Gains (losses) on disposal of assets not classified as non-current assets held for sale, total Gains (Losses) On Disposals Of Non-Financial Assets, Net Gains (Losses) On Disposals Of Non-Financial Assets, Net Securitisation Swap Securitisation Swap [Member] Securitisation Swap Changes in the fair value of equity instruments measured at fair value through other comprehensive income Income tax relating to hedges of investments in equity instruments included in other comprehensive income Percentage increase in non-performing loans ratio Increase In Non-Performing Loans Ratio Increase In Non-Performing Loans Ratio Maximum amount of incentive Deferred Variable Remuneration, Maximum Total Amount Of Incentive Deferred Variable Remuneration, Maximum Total Amount Of Incentive Reserves of subsidiaries Reserves Of Subsidiaries A component of equity representing reserves of subsidiaries. Disclosure Of Other Equity Instruments And Own Shares [Table] Disclosure Of Other Equity Instruments And Own Shares [Table] Disclosure Of Other Equity Instruments And Own Shares [Table] Difference between total shareholder return and peer group (in percentages) Difference Between Total Shareholder Return And Peer Group, Percentage Difference Between Total Shareholder Return And Peer Group, Percentage Without considering the Public Administration Loans And Receivables Without Considering Public Administration [Member] This member stands for loans and receivables without considering the Public Administration. Number of countries with Superdigital implemented Deferred Variable Remuneration, Milestone, Pago Nxt, Number Of Countries With Superdigital Implemented Deferred Variable Remuneration, Milestone, Pago Nxt, Number Of Countries With Superdigital Implemented Shares owned by third parties and received as security (in shares) Number Of Shares Owned By Third Parties Received As Security The number of shares owned by third parties and received as security. OTHER ASSETS Other assets Other Other assets Other Other non-financial assets Other non-financial assets Level 1 Level 1 of fair value hierarchy [member] Variable long-term employee benefits, deferred remuneration Key Management Personnel Compensation, Variable Long-Term Employee Benefits, Deferred Remuneration Key Management Personnel Compensation, Variable Long-Term Employee Benefits, Deferred Remuneration Other proceeds related to financing activities Other Inflows Of Cash Classified As Financing Activities Inflows of cash, classified as financing activities, that the entity does not separately disclose in the same statement or note. Santander Bank Polska and Santander Consumer Bank Poland Santander Bank Polska And Santander Consumer Bank Poland [Member] Santander Bank Polska And Santander Consumer Bank Poland Options granted (in shares) Number of share options granted in share-based payment arrangement Disclosure of detailed information about property, plant and equipment [line items] Disclosure of detailed information about property, plant and equipment [line items] Disclosure of detailed information about property, plant and equipment [line items] Mortgage backed assets Mortgage Backed Assets The amount of mortgage backed assets. Estimated future benefit payable Estimated Future Benefit Payable From Defined Benefit Plans The estimated amount, at the balance sheet date, of the future benefits payable during the specified period from defined benefit plans. Reverse repurchase agreements Repurchase Agreements Liabilities [Member] This member stands for financial liabilities that are repurchase agreements. Expected return on plan assets Return On Plan Assets Net Defined Benefit Liability Asset Including Interest Return On Plan Assets Net Defined Benefit Liability Asset Including Interest Other items Non-Controlling Interest Excluding Accumulated Other Comprehensive Income The amount of equity in a subsidiary not attributable, directly or indirectly, to a parent other than accumulated other comprehensive income. Digital Transformation Award Digital Transformation Award [Member] Digital Transformation Award Schedule of detail, by origin, of gains/losses on financial assets and liability Disclosure Of Gains (Losses) On Financial Assets And Liabilities [Table Text Block] Tabular disclosure of gains and losses on financial assets and liabilities. Dividends Dividends paid Dividends paid, classified as financing activities Fixtures Fixtures and fittings [member] Schedule summarising attendance fees Disclosure Of Transactions Between Related Parties, Remuneration, Attendance Fees Explanatory [Table Text Block] Tabular disclosure of remuneration for attendance fees between the entity and its related parties. Loans Loan [Member] Loan Fx forward Foreign Exchange Forward Contract [Member] Information pertaining to foreign exchange forward contracts. Share in other income and expenses recognised in investments, joint ventures and associates Share in other income and expenses recognised in investments, joint ventures and associates Amount Recognised In Other Comprehensive Income And Subject To Reclassification To Profit Or Loss Relating To Investments In Associated Entities The portion of The portion of other recognized income and expense of investments in subsidiaries, joint ventures and associated entities that is recognised in other comprehensive income and may be reclassified to profit or loss. Repurchase trust, group's effective participation (in percentage) Repurchase Trust, Group Effective Participation, Percentage Repurchase Trust, Group Effective Participation, Percentage Change in fair value of hedged item for ineffectiveness assessment Gain (loss) on change in fair value of hedged item used as basis for recognising hedge ineffectiveness FINANCIAL LIABILITIES HELD FOR TRADING Financial liabilities held for trading FINANCIAL LIABILITIES HELD FOR TRADING Financial liabilities at fair value through profit or loss that meet definition of held for trading Total net cash outflows (denominator) High-Quality Liquid Assets, Cash Outflow (Inflow) High-Quality Liquid Assets, Cash Outflow (Inflow) Change in DVA (as a percent) Financial Instruments, Debt Valuation Adjustment, Increase (Decrease) Increase (decrease) in debt valuation adjustment from prior year as a percent. Schedule of the breakdown of loans and advances to customers Disclosure Of Loans And Advances To Customers Breakdown [Table Text Block] Tabular disclosure of breakdown of loans and advances to customers. Number of employees with disabilities at end of period Number Of Employees With Disabilities At End Of Period The number of employees with disabilities at end of period. Issuance by Banco Santander S.A. in December 2020 Issuance By Banco Santander S.A. In December 2020 [Member] Issuance By Banco Santander S.A. In December 2020 Non-current assets and liabilities associated with non-current assets held for sale Description of accounting policy for non-current assets or disposal groups classified as held for sale [text block] Percentage increase in credit risk, excluding exchange rate Percentage Increase In Credit Risk, Excluding Exchange Rate Percentage Increase In Credit Risk, Excluding Exchange Rate Cheques and other Credit Related Fee And Commission Income Cheques And Other The amount of income recognised from credit-related fees and commissions from cheques and other. Deferred tax liability (asset) at beginning of period Deferred tax liability (asset) at end of period Deferred tax liability (asset) FINANCIAL LIABILITIES DESIGNATED AT FAIR VALUE THROUGH PROFIT OR LOSS Financial liabilities designated at fair value through profit or loss Other financial liabilities at fair value through profit or loss Financial liabilities at fair value through profit or loss, designated upon initial recognition or subsequently Other adjustments Other adjustments for non-cash items Level 2 eligible capital (EUR million) Tier II IFRS Tier Two Risk Based Capital Tier 2 risk-based capital as defined in the international regulations. Current liabilities Current liabilities Rest of the world Rest Of World [Member] Rest of World. Paid premiums Insurance Contracts Linked To Pensions, Increase Due To Premiums Paid Insurance contracts linked to pensions, increase in plan assets due to premiums paid. Net commissions Net fee income Fee and commission income (expense) Schedule of financial assets measured at other than fair value Disclosure Of Financial Assets Measured At Other Than Fair Value [Table Text Block] The disclosure of financial assets measured at other than fair value. Ineffective recognised in the income statement Gain (loss) on hedge ineffectiveness recognised in profit or loss Schedule of financial assets that are either past due or impaired, with or without collateral Disclosure Of Financial Assets That Are Either Past Due Or Impaired, With Or Without Collateral [Table Text Block] Disclosure Of Financial Assets That Are Either Past Due Or Impaired, With Or Without Collateral Share Buyback Program [Domain] Share Buyback Program [Domain] Share Buyback Program [Domain] Net profit from transaction with treasury shares Net Purchase (Sale) Of Treasury Shares Net Purchase (Sale) Of Treasury Shares Interest income / (charges) after provision for credit losses Net Interest And Dividend Income Expense After Provision For Credit Losses The amount of net interest income (expense) plus dividends received from affiliates after provision for credit losses during the period Continuing and discontinued operations [axis] Continuing and discontinued operations [axis] Number of independent divisions Financial Instruments Management, Number Of Independent Divisions Number of independent divisions from which responsibilities are distributed for the systematic valuation and management of financial instruments. Subordinated issue, mid-swap rate term Subordinated Issue, Mid-Swap Rate Term Subordinated Issue, Mid-Swap Rate Term Schedule of components of other comprehensive income Disclosure Of Other Comprehensive Income Components [Table Text Block] Tabular disclosure of the components of other comprehensive income. Disclosure of temporary difference, unused tax losses and unused tax credits [line items] Disclosure of temporary difference, unused tax losses and unused tax credits [line items] Repaid By Banco Santander S.A. In July 2025 Repaid By Banco Santander S.A. In July 2025 [Member] Repaid By Banco Santander S.A. In July 2025 Share buyback program, amount Share Buyback Program, Amount Share Buyback Program, Amount Net increase/(decrease) in operating assets Net increase/decrease in operating assets Adjustments For Decrease Increase In Operating Assets Adjustments for decrease (increase) in operating assets to reconcile profit (loss) to net cash flow from (used in) operating activities. Changes in the fair value of equity instruments measured at fair value with changes in other comprehensive income (hedging instrument) Other Reserves, Other Comprehensive Income, Before Tax, Gains (Losses) On Hedged Instrument Other Reserves, Other Comprehensive Income, Before Tax, Gains (Losses) On Hedged Instrument Statement of changes in equity [abstract] Statement of changes in equity [abstract] Valuation of financial instruments Valuation Of Financial Instruments [Member] Valuation Of Financial Instruments Measurement [domain] Measurement [domain] Gross amount of financial assets Gross financial assets subject to offsetting, enforceable master netting arrangements or similar agreements Grupo Santander Grupo Santander [Member] Grupo Santander Santander Spain and Banco Santander Santander Spain And Banco Santander [Member] Santander Spain And Banco Santander Unconsolidated structured entities [domain] Unconsolidated structured entities [domain] Foreign exchange rates [abstract] Foreign exchange rates [abstract] Provisions for employee benefits Provisions for employee benefits Deferred payment, long term, percentage paid in shares Variable Remuneration, Deferred Payment, Long Term, Percentage Paid In Shares Variable Remuneration, Deferred Payment, Long Term, Percentage Paid In Shares Customers funds Customer Funds [Member] Customer Funds Provisions for taxes Provisions For Taxes [Member] This member stands for provisions for taxes. Maximum exposure to credit risk Maximum exposure to credit risk Other gains (losses) Other Gains Or Losses [Member] Other Gains Or Losses Significant unobservable input, assets Significant unobservable input, assets Share in other income and expenses recognised in investments, joint ventures and associates Amount Recognised In Other Comprehensive Income And Accumulated In Equity Relating To Investments In Associated Entities The portion of other recognized income and expense of investments in subsidiaries, joint ventures and associated entities that is recognised in other comprehensive income and accumulated in equity. CHANGES IN THE FAIR VALUE OF HEDGED ITEMS IN PORTFOLIO HEDGES OF INTEREST RATE RISK Changes in the fair value of hedged items in portfolio hedges of interest rate risk Accumulated fair value hedge adjustment on hedged item included in carrying amount, assets Shareholders’ equity on public balance sheet Equity Attributable To Owners Of Parent, Before Valuation Adjustments Equity Attributable To Owners Of Parent, Before Valuation Adjustments Other provisions Other provisions Provisions For Taxes And Other Legal Contingencies And Other Provisions [Member] This member stands for provisions for taxes and other legal contingencies and other provisions. Variable - immediate payment in instruments Variable remuneration in shares Key Management Personnel Compensation, Share-Based Payment, Variable Immediate Payments The amount of variable compensation to key management personnel in the form of share-based payments for short term benefits. Transfer from liabilities to equity Transfer From Liabilities To Equity Transfer From Liabilities To Equity Number of variable long-term employee benefits, deferred remuneration Key Management Personnel Compensation, Number Of Variable Long-Term Employee Benefits, Deferred Remuneration Key Management Personnel Compensation, Number Of Variable Long-Term Employee Benefits, Deferred Remuneration Types of risks [domain] Types of risks [domain] SAM Investment Holdings Limited SAM Investment Holdings Limited [Member] SAM Investment Holdings Limited [Member] Recognised assets representing continuing involvement in fully derecognised loans Recognised assets representing continuing involvement in derecognised financial assets Probability weighting Probability Weighting Valuation Technique [Member] Probability Weighting Valuation Technique Issuance By Banco Santander SA In January 2024 Issuance By Banco Santander SA In January 2024 [Member] Issuance By Banco Santander SA In January 2024 Cash Cash on hand Condensed cash flow statements Condensed Cash Flow Statement [Table Text Block] Subsidiaries [axis] Subsidiaries [axis] Share premium Disclosure Of Share Premium [Text Block] The entire disclosure for share premium. Interest paid Interest paid, classified as operating activities Geographical [Domain] Geographical [Domain] Provisions for pensions (note 25) Pension Interest Expense Charged To Provision Pension Interest Expense Charged To Provision FINANCIAL ASSETS HELD FOR TRADING Financial assets held for trading Financial assets held for trading Financial assets at fair value through profit or loss, classified as held for trading Actuarial (gains)/losses Actuarial gains/(losses) Actuarial gains/(losses) Actuarial Gains (Losses) Defined Benefit Liability Asset The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) that result in remeasurements of the net defined benefit liability (asset). Incorporation of Group companies, net Incorporation of Group companies, net Net Inclusion Of Entities In The Group Defined Benefits Net inclusion of entities in the Group for defined benefits. Additions / disposals (net) Additions And Disposals To Property Plant And Equipment The net amount of additions or disposals to property, plant and equipment. Net defined benefit liability (asset) [domain] Net defined benefit liability (asset) [domain] Disposal Group Name [Domain] Disposal Group Name [Domain] Disposal Group Name [Domain] In which, restricted cash Restricted cash and cash equivalents Schedule of maturity analysis of assets and guarantees received and committed Disclosure of maturity analysis for financial assets held for managing liquidity risk [text block] Financial Conduct Authority (FCA) Review of The Vehicle Finance Market Financial Conduct Authority (FCA) Review of The Vehicle Finance Market [Member] Financial Conduct Authority (FCA) Review of The Vehicle Finance Market Other asset - backed securities SME's average maturities Other Asset Backed Securities SME Average Maturity Represents the average maturity for other assets - backed securities SME's. Insurance contracts by components Insurance contracts by components [domain] José Antonio Álvarez José Antonio Álvarez Jose Antonio Alvarez [Member] The member that represents an individual key personnel named Jose Antonio Alvarez Alvarez. Auto Auto [Member] Auto Auditor Firm [Domain] Auditor Firm [Domain] Auditor Firm [Domain] Percentage employees may reduce the average purchase and sale prices of shares under the Sharesave Scheme Percentage Employees Reduce Average Purchase Price Of Shares Percentage employees may reduce the average purchase and sale prices of shares under the Sharesave Scheme. "Planos Econmicos" Planos Economicos [Member] This member stands for "Planos Economicos". Items not reclassified to profit or loss Income Tax Relating To Components Of Other Comprehensive Income That Will Not Be Reclassified To Profit Or Loss Including Share Of OCI Of Associates And Joint Ventures The amount of income tax relating to amounts recognised in other comprehensive income that will not be reclassified to profit or loss including share of OCI of associates and joint ventures accounted for using equity method. Non-financial corporations and individual entrepreneurs (non-financial business activity) Non-financial institutions and individual shareholder Non Financial Corporations And Individual Entrepreneurs [Member] This member stands for non-financial corporations and individual entrepreneurs (Non-financial business activity) customers. CHANGES IN THE FAIR VALUE OF HEDGED ITEMS IN PORTFOLIO HEDGES OF INTEREST RATE RISK Changes in the fair value of hedged items in portfolio hedges of interest rate risk Changes in the fair value of hedged items in portfolio hedges of interest rate risk Accumulated fair value hedge adjustment on hedged item included in carrying amount, liabilities Revaluation gains (losses) Gains (Losses) On Non-Current Assets Classified As Held For Sale, Before Tax Gains (Losses) On Non-Current Assets Classified As Held For Sale, Before Tax AAA IFRS Standard Poors AAA Rating [Member] AAA credit rating as defined by the external credit rating agency, Standard & Poor's. Impaired assets Impaired Assets Financial Instrument Type [Member] Information pertaining to impaired assets, as a type of financial instrument. Financial assets at fair value through profit or loss Financial assets at fair value through profit or loss Financial Assets At Fair Value Through Profit Or Loss And Non-Trading Financial Assets At Fair Value Through Profit Or Loss Mandatorily Measured At Fair Value Financial Assets At Fair Value Through Profit Or Loss And Non-Trading Financial Assets At Fair Value Through Profit Or Loss Mandatorily Measured At Fair Value Santander Insurance Services UK Limited Santander Insurance Services UK Limited [Member] Santander Insurance Services UK Limited Disclosure of fair value measurement of assets [table] Disclosure of fair value measurement of assets [table] Disclosure of initial application of standards or interpretations [line items] Disclosure of initial application of standards or interpretations [line items] Disclosure of details of fee and commission expense Disclosure Of Fee And Commissions Expense [Table Text Block] The tabular disclosure of fees and commissions expense. Increase (decrease) compared to last year increase in fair value of financial liability Increase (Decrease) Compared To Last Year In Fair Value Of Financial Liability, Attributable To Changes In Credit Risk Of Liability Increase (Decrease) Compared To Last Year In Fair Value Of Financial Liability, Attributable To Changes In Credit Risk Of Liability Risk management, VaR calculation, time frame Risk Management, VaR Calculation, Time Frame Risk Management, VaR Calculation, Time Frame Other comprehensive income Accumulated other comprehensive income [member] Subordinated debentures Subordinated Debentures [Member] Subordinated Debentures Investment securities Investment Securities Investment Securities U.C.I., S.A. Union De Creditos Inmobiliarios SA EFC [Member] Information pertaining to Union de Creditos Inmobiliarios S.A., EFC. Discontinued operations (Note 37) Tax expense (income) relating to profit (loss) from ordinary activities of discontinued operations Exchange differences Balance at beginning of year Balance at end of year Reserve of exchange differences on translation Banco Popular’s Compensation request Banco Popular’s Compensation Request [Member] Banco Popular’s Compensation Request Subordinated issue, US government bond term Subordinated Issue, US Government Bond Term Subordinated Issue, US Government Bond Term Foreign currency purchases and sales Foreign Currency Purchases And Sales [Member] This member stands for foreign currency purchases and sales. G-SIB, capital buffer percentage Global Systemically Important Banks, Capital Buffer Percentage Percentage of capital buffer specified in total loss absorbing capacity (TLAC) requirements. Schedule of related party transactions Disclosure of transactions between related parties [text block] TOTAL LIABILITIES AND EQUITY Equity and liabilities US United States UNITED STATES Property, plant and equipment [abstract] Property, plant and equipment [abstract] Bank of New York Mellon Corporation Bank Of New York Mellon Corporation [Member] Represents information pertaining to The Bank of New York Mellon Corporation. PD percentage increase from initial recognition Probability Of Default, Percentage Increase From Initial Recognition Probability Of Default, Percentage Increase From Initial Recognition Business combinations [domain] Business combinations [domain] Impairment of financial assets Description of accounting policy for impairment of financial assets [text block] Loan commitments and Other commitments granted Outstanding commitments made by entity, related party transactions Non- financial services Non-Financial Services Other Income Operating The amount of non-financial services operating income that the entity does not separately disclose in the same statement or note. Exchange differences and other items Exchange differences and other changes Exchange differences and other Increase (decrease) through foreign exchange and other movements, financial assets Threshold percentage in determining classification of Stage 2 Determination Of Stage 2 Classification, Threshold Determination Of Stage 2 Classification, Threshold Interest rate Interest rate, measurement input [member] Subordinated issue, adjustment to reference rate Subordinated Issue, Adjustment To Interest Rate Basis, Subsequent To Initial Interest Rate Period The adjustment to the basis (reference rate) used for calculation of the interest rate on the subordinated issue, after the initial interest rate period. More than 40% and less than or equal to 60% LTV 40 To 60 Percent [Member] Loan-to-value (LTV) ratio from 40 to 60%. A) Not designated elements - linked to a time period Not Designated Items, By Time Period [Member] Not Designated Items, By Time Period Joint ventures [domain] Joint ventures [domain] Complementary dividend Complementary Dividend [Member] Complementary Dividend Banco Santander, S.A., November 2023 Issuance By Banco Santander S.A. In November 2023, Second Series [Member] Issuance By Banco Santander S.A. In November 2023, Second Series Schedule of preferred shares and securities Disclosure Of Balance Of Preference Shares And Preferred Securities [Table text block] Tabular disclosure of balance of preference shares and preferred securities at the balance sheet date. AT1-excesses-subsidiaries Excess Tier One Risk Based Capital, Subsidiaries The amount by which the company's Tier 1 Risk Based Capital exceeds the minimum required for capital adequacy purposes attributable to subsidiaries. Number of tranches Exposure To Credit Risk, Number Of Tranches Exposure To Credit Risk, Number Of Tranches Percentage increase in nonperforming ratio Increase In Non-Performing Ratio, Percent Increase In Non-Performing Ratio, Percent Capital gains by valuation Reserve Of Gains And Losses From Investment In Equity Instruments, Accumulated Gains The portion of the reserve of gains and losses from investments in equity instruments that represents accumulated revaluation gains. Ordinary profit assumption Regulatory Capital Adjustment, Accrued Dividend, Ordinary Profit Assumption, Percentage Regulatory Capital Adjustment, Accrued Dividend, Ordinary Profit Assumption, Percentage USD/COP United States Dollar And Colombia Peso [Member] United States Dollar And Colombia Peso Provisions and contingent liabilities (assets) Description of accounting policy for contingent liabilities and contingent assets [text block] Beneficiaries with target total variable remuneration between 1.7 and 2.7 million euros Beneficiaries With Target Total Variable Remuneration Between 1.7 And 2.7 Million Euros [Member] Beneficiaries With Target Total Variable Remuneration Between 1.7 And 2.7 Million Euros Cards Credit Related Fee And Commission Income Cards The amount of income recognised from credit-related fees and commissions from cards. Disclosure of net defined benefit liability (asset) [table] Disclosure of net defined benefit liability (asset) [table] US dollar USD United States of America, Dollars Fair value of financial instruments Disclosure of fair value of financial instruments [text block] Diluted earnings per share [abstract] Diluted earnings per share [abstract] Cap&Floor Caps/Floors [Member] Caps/Floors [Member] Miscellaneous assets [abstract] Miscellaneous assets [abstract] Disclosure of financial assets that are either past due or impaired [line items] Disclosure of financial assets that are either past due or impaired [line items] Minimum number of accounts/contracts per employee Share Based Payment Arrangement Single Employee Minimum Number Of Contracts Number of accounts/contracts a single employee may have under a share-based payment arrangement. Acquisition for the year (net) Increase (Decrease) Through Business Combinations Deferred Tax Asset The increase (decrease) in deferred tax asset resulting from business combinations Corporate loans Corporates Loans to corporate entities [member] Others increases or (-) decreases in equity Increase (decrease) through other changes, equity Categories of financial liabilities [domain] Categories of financial liabilities [domain] Annual emoluments, per director Key Management Personnel Compensation, Director Compensation, Per Director Key Management Personnel Compensation, Director Compensation, Per Director Related parties Disclosure of related party [text block] Intangible assets Impairment loss recognised in profit or loss, intangible assets and goodwill Level 3 Level 3 of fair value hierarchy [member] IFRS Statement [Table] Disclosure Of IFRS Statement [Table] Schedule reflecting a Statement of Income, Statement of Cash Flows, Statement of Financial Position, or other statement as needed. Total Income tax relating to components of other comprehensive income Short sales Financial Liabilities Attributable To Short Sales The amount of financial liabilities attributable to short sales. Options, vesting period Deferred Variable Remuneration, Options, Vesting Period Deferred Variable Remuneration, Options, Vesting Period Group LCR ratio (%) Group Liquidity Coverage Ratio Group Liquidity Coverage Ratio Gain (loss) recognised on measurement to fair value less costs to sell or on disposal of assets or disposal groups constituting discontinued operation Gain (loss) recognised on measurement to fair value less costs to sell or on disposal of assets or disposal groups constituting discontinued operation Unobservable inputs [axis] Unobservable inputs [axis] Disclosure of classes of share capital [table] Disclosure of classes of share capital [table] SPIRE SA Compartment 2023-374 SPIRE SA Compartment 2023-374 [Member] SPIRE SA Compartment 2023-374 Assets written off Decrease through write-off, financial assets Legal case related to infringement notices initiated by tax authorities regarding the offsetting of tax losses Legal Case Related To Infringement Notices Initiated By Tax Authorities Regarding Offsetting Tax Losses [Member] Legal Case Related To Infringement Notices Initiated By Tax Authorities Regarding Offsetting Tax Losses [Member] Current service cost Defined Benefit Plans, Service Cost Amount of service cost expense recognized related to defined benefit plan. Other Other Market Risk [Member] This member stands for all other market risks, except trading risk. Summary of financial information on the main associates and joint ventures Disclosure Of Financial Information On Main Associates And Joint Ventures [Table Text Block] Tabular Summary Of Financial Information on Main Associates and Joint Ventures. REVALUATION RESERVES Revaluation reserve Royal Decree-Law 7/1996 Revaluation surplus Banco Santander International SA (former Banco Santander (Suisse) S.A) Banco Santander International SA [Member] Banco Santander International SA Schedule of estimated effect of a 1% change in the euro against the corresponding currency Schedule Of Sensitivity Analysis Of Consolidated Equity And Profit Of 1% Appreciation/Depreciation Of Euro [Table Text Block] Tabular disclosure of a sensitivity analysis showing the estimated effect of changes in the foreign currency on consolidated equity and consolidated profit. Santander US Auto Santander US Auto [Member] Santander US Auto Post-employment plans Post employment plans Pensions And Other Employment Defined Benefit Obligations Provision [Member] This member represents the provision for pensions and other employment defined benefit obligations. Global minimum tax Pillar Two Current tax expense (income), related to Pillar Two income taxes Banco Santander, S.A., January 2020 Issuance By Banco Santander S.A. In January 2020 [Member] Issuance By Banco Santander S.A. In January 2020 Base risk Base Risk [Member] Base Risk Structured Notes Structured Notes [Member] Structured Notes Disclosure of maturity analysis for non-derivative financial liabilities [line items] Disclosure of maturity analysis for non-derivative financial liabilities [line items] Minorities, taxes and others Non-Controlling Interest Relating To Cash Flow Hedges Of Other Comprehensive Income The amount of minorities relating to amounts recognised in other comprehensive income in relation to cash flow hedges. Brazil And Openbank Segment Brazil And Openbank Segment [Member] Brazil And Openbank Segment Fair value of plan, initial achievement Percentage Of Fair Value Of Initial Achievement Of Performance Share Plan Fair value of performance plan as a percentage of the maximum initial achievement ratio. Total certain assets Certain Financial Assets The total of certain assets from the balance sheet including Cash, cash balances at central banks and other deposits on demand; Financial assets available-for-sale; loans and receivables and investments held-to-maturity. Changes in the scope of consolidation Increase (Decrease) Through Changes In Scope Of Consolidation Financial Assets The amount of increase (decrease) in financial assets due to changes in the scope of consolidation. Deferred Conditional Variable Remuneration Plan Twelfth Cycle 2023 Deferred Conditional Variable Remuneration Plan Thirteenth Cycle 2023 [Member] Deferred Conditional Variable Remuneration Plan Thirteenth Cycle 2023 SC Germany S.A., Compartment Consumer 2024-2 SC Germany S.A., Compartment Consumer 2024-2 [Member] SC Germany S.A., Compartment Consumer 2024-2 Schedule of breakdown by type of instrument Disclosure of detailed information about financial instruments [text block] Reclassification of financial assets at fair value through other comprehensive income Financial Assets Reclassified From Fair Value With Changes In Other Comprehensive Income [Member] Financial Assets Reclassified From Fair Value With Changes In Other Comprehensive Income Banco Popular Espanol, S.A. Banco Popular Espanol S.A. [Member] This member represents Banco Popular Espanol, S.A. CET1 phase-in percentage Level 1 ordinary capital coefficient (CET 1) Common Equity Tier One Capital Ratio1 Percentage of Common Equity Tier One Risk-based Capital to total risk-weighted assets, as defined by regulatory framework. From goodwill Foreign Exchange Gain (Loss), Goodwill Foreign Exchange Gain (Loss), Goodwill Other Other assets [member] Percentage of entity economic capital Percentage Of Entity Economic Capital Represents the country heads of countries that are a percentage of the entity's economic capital. Separate management entities [axis] Separate management entities [axis] Core capital ratio for foreign exchange rate risk Percent Of Core Capital Ratio Covered Against Risk The percent of the core capital ratio that is covered by risk management practices against the specified risk. ALSO, revise label to Core capital ratio coverage, as a percent Difference Increase (decrease) in financial assets Classes of other provisions [axis] Classes of other provisions [axis] Brokerages and intermediaries Brokerage fee expense Debt securities Disclosure of debt instruments [text block] Schedule of changes in fair value of financial assets and liabilities calculated using internal models Disclosure Of Changes In Fair Value Of Financial Assets And Liabilities Calculated Using Internal Models [Table Text Block] Disclosure Of Changes In Fair Value Of Financial Assets And Liabilities Calculated Using Internal Models Other adjustments Material reconciling items [member] EUR/GBP Euro And Pound Sterling [Member] Euro And Pound Sterling Payment Solutions Payment Solutions Segment [Member] Payment Solutions Segment Additional information [abstract] Ratio of variable to fixed pay components Ratio Of Variable To Fixed Pay Components Ratio Of Variable To Fixed Pay Components Average purchase price of bank shares (in euro per share) Weighted Average Share, Purchase Price The weighted average purchase price per share. Fair value Not measured at fair value in statement of financial position but for which fair value is disclosed [member] Profit (loss) from discontinued operations (non controlling interest net) Profit (loss) from discontinued operations attributable to ordinary equity holders of parent entity, used in calculating diluted earnings per share Maximum exposure limit, percentage Maximum Exposure Limit, Percentage Maximum Exposure Limit, Percentage Shares of foreign companies Financial Assets, Shares Of Foreign Companies [Member] This member stands for instruments held by the entity in the assets of foreign companies. Deferred conditional variable remuneration plan and linked to objectives (2019) Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2019 [Member] Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2019 Evolution projection period Evolution Projection Period Represents the evolution of macroeconomic scenarios projection period. Adjustments made to obtain the cash flows from operating activities Adjustments to profit Adjustments to reconcile profit (loss) other than changes in working capital Optimistic scenario 1 Optimistic Scenario One [Member] Represents information pertaining to Optimistic scenario one. Disclosure of credit risk exposure [line items] Disclosure of credit risk exposure [line items] Decrease in fair value liabilities due to changes in inputs Decrease in fair value measurement due to change in multiple unobservable inputs to reflect reasonably possible alternative assumptions, liabilities Schedule of status and changes of the defined benefit obligations Disclosure of defined benefit plans [text block] Schedule of actuarial assumptions used to calculate defined benefit obligations Disclosure Of Actuarial Assumptions Used To Calculate Defined Benefit Obligations [Table Text Block] Disclosure of actuarial assumptions used to calculate defined benefit obligations. Marketable debt securities Schedule Of Market Debt Securities [Text Block] Schedule Of Market Debt Securities Other Other Related Party Transactions The amount of related-party transactions classified as other. Disclosure of maturity analysis for non-derivative financial liabilities [table] Disclosure of maturity analysis for non-derivative financial liabilities [table] Repaid by Banco Santander S.A. in February 2024 Repaid By Banco Santander S.A. In February 2024 [Member] Repaid By Banco Santander S.A. In February 2024 Ordinary shares Ordinary shares [member] Schedule of changes in impairment losses on debt instruments Schedule of changes in loss allowance and gross carrying amount Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [text block] LIABILITIES ASSOCIATED WITH NON-CURRENT ASSETS HELD FOR SALE Total Liabilities associated with non-current assets held for sale Liabilities included in disposal groups classified as held for sale Other directors Other Directors [Member] This member stands for directors, other than current and retired executive directors. Minimum migratable virtual machines on cloud technology (in percentage) Deferred Variable Remuneration, Milestone, One Common Mobile Experience, Minimum Migratable Virtual Machines On Cloud Technology, Percentage Deferred Variable Remuneration, Milestone, One Common Mobile Experience, Minimum Migratable Virtual Machines On Cloud Technology, Percentage Reclassified amount of reserves to the income statement Amounts transferred to income statements Reclassification Adjustments Of Cover Transaction Affecting Profit Or Loss, Before Tax The amount of reclassification adjustments on hedges for which the hedged item affected profit or loss, before tax. Non-managed marketed funds Non-Managed Marketed Funds The amount of non-managed marketed funds held by the entity at the balance sheet date. Gross carrying amount Cost Gross carrying amount [member] Schedule summarising maximum number of shares to be delivered and actual number of shares delivered Disclosure Of Shares Assigned Between Related Parties, Remuneration, Maximum Number Of Shares To Be Delivered And Actual Number Of Shares Delivered [Table Text Block] Disclosure Of Shares Assigned Between Related Parties, Remuneration, Maximum Number Of Shares To Be Delivered And Actual Number Of Shares Delivered Applicable tax rate in Spain Applicable tax rate Property, plant and equipment by operating lease status [domain] Property, plant and equipment by operating lease status [domain] Executive directors and Senior management Executive Directors And Senior Management [Member] Executive Directors And Senior Management Other operating liabilities Adjustments for increase (decrease) in other liabilities Issuance of own equity instruments Proceeds from issuing shares Henrique de Castro Henrique Manuel Drummond Borges Cirne De Castro [Member] Mr. Henrique Manuel Drummond Borges Cirne De Castro [Member] Market price Market Price, Measurement Input [Member] Market Price, Measurement Input Total Europe Europe [Member] Secucor Finance 2025-1 Designated Activity Company Secucor Finance 2025-1 Designated Activity Company [Member] Secucor Finance 2025-1 Designated Activity Company 2026 Within 1 year Not later than one year [member] Profit/(loss) attributable to the parent, increase (decrease) in percentage Profit Loss Attributable To Owners Of Parent, Increase (Decrease), Percentage Profit Loss Attributable To Owners Of Parent, Increase (Decrease), Percentage Selling, general and administrative expense [abstract] Number of prospective macroeconomic scenarios Number Of Prospective Macroeconomic Scenarios Represents the number of prospective macroeconomic scenarios. Attendance fees and commissions per meeting Key Management Personnel Compensation, Attendance Fees Per Meeting The amount of compensation paid per meeting, per director, for attendance fees and commissions. Expenses from insurance and reinsurance contracts Expenses From Insurance And Reinsurance Contracts Recognised In Profit Or Loss Amount of expense included in profit or loss related to liabilities under insurance contracts and reinsurance contracts. Shares of Spanish companies Financial Assets, Shares Of Domestic Companies [Member] This member stands for instruments held by the entity in the assets of other domestic companies. Current tax liabilities Current tax liabilities Commission income Total commission income Fee and commission income Transfers, exchange differences and other items Increase (Decrease) Through Transfers, Exchange Differences And Other Items In Property Plant And Equipment The increase (decrease) in property, plant and equipment resulting from transfers, exchange differences and other items which are not separately disclosed. Total Auditor's remuneration Auditor's remuneration Long-term debt Non-current portion of non-current borrowings Net amount of financial assets presented in the balance sheet Net financial assets subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position Property, plant and equipment Property, plant and equipment [member] Disclosure of financial assets [line items] Debt Instruments Disclosure of financial assets [line items] Hedges of net investments in foreign operations (effective portion) Other comprehensive income, before tax, hedges of net investments in foreign operations Number of employees accepted the pre-retirement and voluntary redundancy offers Number Of Employees Accepted Pre Retirement And Voluntary Redundancy Offers Number of employees accepted the pre-retirement and voluntary redundancy offers. Tangible assets Description of accounting policy for property, plant and equipment [text block] Pre-retirement cost Pre Retirement Cost Charged To Income Statement Related To Defined Benefits Pre-retirement cost charged to income statement related to defined benefits. Number of operating areas Number Of Operating Areas Represents the number of operating areas. Changes in the fair value of equity instruments measured at fair value with changes in other comprehensive income (hedged item) Other Reserves, Other Comprehensive Income, Before Tax, Gains (Losses) On Hedged Item Other Reserves, Other Comprehensive Income, Before Tax, Gains (Losses) On Hedged Item Market risk Market risk [member] Grupo Santander Disclosure of business combinations [text block] Accrued expenses and deferred income Accrued Expenses And Deferred Income The amount of accruals and deferred income. [Refer: Accruals; Deferred income] RoTE objective, result Variable Remuneration, Deferred Payment, RoTE Objective, Result Variable Remuneration, Deferred Payment, RoTE Objective, Result America Americas [Member] Gain or loss in value - recognized in equity Gain (Loss) In Value, Recognised In Equity The amount of Other reclassification adjustments on cash flow hedges for which the hedged item affected profit or loss, before tax. Interest rate forwards Interest Rate Forwards [Member] Interest Rate Forwards Benefits paid due to settlements Benefits paid by settlements Decrease (increase) in net defined benefit liability (asset) resulting from payments in respect of settlements Liquidity risk Liquidity risk [member] Issued by financial institutions Debt Securities Issued By Financial Institutions [Member] This member stands for debt securities issued by financial institutions. Disclosure of risk management strategy related to hedge accounting [table] Disclosure of risk management strategy related to hedge accounting [table] Employee with disabilities, threshold degree of disability Employees With Disabilities, Threshold Degree Of Disability The degree of disability at or above which an employee in a particular jurisdiction is considered to be an employee with disabilities for the purposes of headcounts. Adjusted number of shares (in shares) Weighted average number of ordinary shares used in calculating diluted earnings per share Other Loans To Other Entities [Member] Loans To Other Entities Banco Santander, S.A., May 2021 Issuance By Banco Santander S.A. In May 2021, Series In Dollars [Member] Issuance By Banco Santander S.A. In May 2021, Series In Dollars Number of jurisdictions within EU's grey list Number Of Jurisdictions Within EU's Grey List Number Of Jurisdictions Within EU's Grey List Gross amount of financial liabilities Gross financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements Securitised mortgage assets Mortgages [member] Consumer loans Loans to consumers [member] Increase or decrease on obligations if increase in actuarial assumption (as a percent) Increase (Decrease) In Benefit Obligation Due To Reasonably Possible Increase In Actuarial Assumption Percentage increase decrease in benefit obligations due to reasonably possible increase in actuarial assumption. Floating rate debt Floating rate Floating interest rate [member] Subordinated liabilities Repayments of subordinated liabilities Net loan-loss provisions Impairment and reversal of impairment on financial assets, net Impairment And Reversal Of Impairment On Financial Assets, Net The net amount of impairment and reversal of impairment on financial assets. Arbitration matter, amount to be received by entity Arbitration Matter, Amount To Be Received By Entity Arbitration Matter, Amount To Be Received By Entity Classes of intangible assets other than goodwill [domain] Classes of intangible assets other than goodwill [domain] Deferred variable compensation plan linked to multiannual objectives Deferred Variable Compensation Plan Multiannual Objectives [Member] This member represents variable remuneration plan for executive directors and certain executives (including top management). This plan includes the bonus (deferred and conditioned variable compensation plan and the ILP and is intended to defer a portion of the variable remuneration over a specified period. May be paid in cash or in shares. Discounted Cash Flows on swap rate Flow Discounting Method On Swap Rate [Member] Flow Discounting Method On Swap Rate Schedule summarising annual emolument Disclosure Of Transactions Between Related Parties, Remuneration, Annual Emolument [Table Text Block] Tabular disclosure of annual emolument remuneration between the entity and its related parties. Other committees (excluding executive committee) Other Committees [Member] This member stands for those persons serving as members of other committees of the board of directors. Excludes executive committee, audit committee, and risk supervision, regulation, and compliance committee members. Schedule of reconciliation of income tax expense Schedule Of Effective Income Tax Rate Reconciliation1 [Table Text Block] Tabular disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pretax income from continuing operations. Classes of intangible assets and goodwill [axis] Classes of intangible assets and goodwill [axis] Major components of tax expense (income) [abstract] Major components of tax expense (income) [abstract] Preference Shares And Preferred Securities By Issuance [Member] Preference Shares And Preferred Securities By Issuance [Member] This member stands for all issuances of preference shares and preferred securities. It also represents the standard value for the 'Preference shares and preferred securities by issuance' axis if no other member is used. Gains or losses on non-current assets held for sale not classified as discontinued operations Disclosure Of Gains (Losses) On Disposal Of Non-Current Assets Held For Sale Not Classified As Discontinued Operations [Text Block] The disclosure of gains and losses on disposal of assets held for sale that are not discontinued operations. Of which addition Amortisation And Impairment, Additions Intangible Assets Other Than Goodwill The amount of the portion of impairment losses attributable to additions . Disclosure of detailed information about hedges [abstract] Schedule of weights used for current political and economic positions Disclosure Of Weight Associated With Macroeconomic Scenarios [Table Text Block] The tabular disclosure of weight associated with macroeconomic scenarios. Illiquid credit default spread curves Illiquid Credit Default Spread Curves [Member] Illiquid Credit Default Spread Curves Schedule of reconciliation of consolidated profit after tax to operating profit before tax Disclosure Of Reconciliation Of Underlying Results To Statutory Results [Table Text Block] Tabular disclosure of the reconciliation of profit (loss) from reportable segments to the consolidated income (loss) before income tax expense (benefit) and discontinued operations. Includes, but is not limited to, reconciliation after income tax if income tax is allocated to the reportable segment. Other reclassifications Other Reclassification Adjustments On Hedging Instruments Not Designated, Before Tax Other Reclassification Adjustments On Hedging Instruments Not Designated, Before Tax Inflation Derivatives Inflation Derivatives [Member] Inflation Derivatives Minimum period of irregular positions to consider significant increase in risk Minimum Period Of Irregular Positions To Consider Significant Increase In Risk Represents the minimum period of irregular positions to consider significant increase in risk. Undiscounted financial liabilities at amortised cost Undiscounted Financial Liabilities At Amortised Cost The amount of undiscounted financial liabilities at amortised cost. Business combinations carried out Business Combinations Carried Out [Member] Business Combinations Carried Out (-) INTERIM DIVIDENDS Approved dividend Interim Dividends Interim Dividends Mortgage-backed securities loan-to-value ratio (as a percent) Mortgage Backed Securities Loan To Value Ratio Represents the required loan-to-value ratio for mortgage-backed securities. Interest income / (charges) Interest Income Expense Net Plus Dividends From Affiliates Net amount of interest income, interest expense and dividends received from affiliates Profit/(loss) attributable to non-controlling interests Profit attributable to non-controlling interests Non-controlling interests Profit (loss), attributable to non-controlling interests Change of perimeter Increase (Decrease) Through Other Changes, Financial Assets Increase (Decrease) Through Other Changes, Financial Assets Amounts transferred to income statement Reclassification Adjustments On Non-Current Assets Classified As Held For Sale, Before Tax Reclassification Adjustments On Non-Current Assets Classified As Held For Sale, Before Tax EQUITY Equity [abstract] Other Foreign Countries Not Including Countries in EU Other Foreign Countries Not Including Countries In EU [Member] This member stands for foreign countries other than Spain and countries in EU. Santander Consumo 6, F.T. Santander Consumo 6, F.T. [Member] Santander Consumo 6, F.T. More than 80% and less than or equal to 100% IFRS LTV 80 To 100 Percent [Member] Loan-to-value (LTV) ratio from 80 to 100%. Element name and standard label in LTV [numeric lower end] to [numeric higher end] Percent [Member] format. Issuance by Banco Santander S.A. in October 2021 Issuance By Banco Santander S.A. In October 2021 [Member] Issuance By Banco Santander S.A. In October 2021 Period for investment in bank shares from date of termination Period For Investment In Bank Shares From Date Of Termination The period of investment in bank shares from date of termination. Project Quasar Investments 2017 S.L. Project Quasar Investments 2017 S.l. [Member] This member stands for the entity's investment in Project Quasar Investments 2017, S.L. Insurance contracts linked to pensions Insurance Contracts Linked To Pensions [Abstract] N/A Coming from collection and payment services Fee And Commission Income, Collection And Payment Services [Abstract] n/a. Assets and liabilities classified as held for sale Assets and liabilities classified as held for sale [member] Other operating costs Other Operating Cost, Segment Reporting Other Operating Cost, Segment Reporting Forward estimation Forward Estimation Valuation Technique [Member] Forward Estimation Valuation Technique Other reclassifications Other Reclassification Adjustments On Hedges Of Net Investments In Foreign Operations, Before Tax Other Reclassification Adjustments On Hedges Of Net Investments In Foreign Operations, Before Tax Portion already submitted for conversion Deferred Tax Assets, Portion Already Submitted For Conversion The portion of deferred tax assets already submitted to taxing authorities. Percent of total assets encumbered Assets Pledged As Collateral For Liabilities Or Contingent Liabilities, Percent Of Total The percent of total assets that the entity has pledged as collateral for liabilities or contingent liabilities. Increase in adjustment to gross carrying amount, mortgage loans Increase (Decrease) In Adjustment To Gross Carrying Amount, Mortgage Loans Increase (Decrease) In Adjustment To Gross Carrying Amount, Mortgage Loans Changes in Bonds and debentures Disclosure of fair value measurement of liabilities [line items] Disclosure of fair value measurement of liabilities [line items] Schedule of changes in fair value of equity instruments that will not be reclassified Disclosure Of Other Comprehensive Income Changes In Fair Value That Will Not Be Reclassified To Profit Or Loss [Table Text Block] The tabular disclosure of changes in the fair value of equity instruments measured at fair value through other comprehensive income that will not be reclassified to profit or loss. Financial assets at fair value through other comprehensive income Financial assets at fair value through other comprehensive income, category [member] Annual social security pension increase rate Actuarial assumption of expected rates of pension increases Non-trading financial assets mandatorily at fair value through profit or loss Financial assets at fair value through profit or loss, mandatorily measured at fair value, category [member] Schedule of accumulated retained earnings and reserves of entities accounted for using the equity method Schedule Of Accumulated Retained Earnings And Reserves Of Entities Accounted For Using The Equity Method [Table Text block] Tabular information related to Accumulated retained earnings and Reserves of entities accounted for using the equity method. Other asset-backed bonds Other Asset Back Bonds [Member] Other Asset Back Bonds. Disclosure of temporary difference, unused tax losses and unused tax credits [table] Disclosure of temporary difference, unused tax losses and unused tax credits [table] Luis Isasi Luis Isasi Fernandez De Bobadilla [Member] Luis Isasi Fernandez De Bobadilla CZK Czech Republic, Koruny Loans to customers, net of impairment losses Loans To Customers, Net Of Impairment Losses The amount of loans, excluding advances and net of impairment losses, to customers such as public sector, financial institutions, non-financial corporations, and households, as of the balance sheet date. Disclosure of information on liabilities secured by financial assets Disclosure Of Financial Liabilities Secured By Financial Assets [Table Text Block] The disclosure of financial liabilities secured by financial assets. Changes in fair value used for calculating hedge ineffectiveness Gain (loss) on change in fair value of hedging instrument used as basis for recognising hedge ineffectiveness Condensed statements of income Condensed Income Statement [Table Text Block] Change in provision assuming 100bp decrease in unemployment rate (as a percent) Percent Change In Provision Assuming 100 Basis Point Decrease In Unemployment Rate Percent Change In Provision Assuming 100 Basis Point Decrease In Unemployment Rate Number of operating segments Reportable Segments, Number Reportable Segments, Number Preference Shares And Preferred Securities By Issuance [Axis] Preference Shares And Preferred Securities By Issuance [Axis] The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table. Pension contribution Key management personnel compensation, post-employment benefits Gain or losses on financial assets and liabilities measured at fair value through profit or loss, net Gains Losses On Financial Assets And Liabilities At Fair Value Through Profit Or Loss Net amount of gains or losses on financial assets and liabilities at fair value through profit or loss. EQUITY INSTRUMENTS ISSUED OTHER THAN CAPITAL Reserve of equity component of convertible instruments Reserve of equity component of convertible instruments Cost of credit (in percent) Cost of risk (in percent) Cost Of Risk, Percent Cost Of Risk, Percent Off-balance-sheet exposures Off-Balance Sheet Exposures [Abstract] No definition available. IFRS Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Disclosure Of IFRS Compliance With Regulatory Capital Requirements Under Banking Regulations [Table] A table disclosing the capital amounts and ratios as of the balance sheet date indicating whether the entity or entities are in compliance with regulatory capital requirements, by entity. Consolidated profit (loss) before tax: Profit (Loss) Before Tax, Including Discontinued Operations Profit (Loss) Before Tax, Including Discontinued Operations Credit Quality [Axis] Credit Quality [Axis] Information by type of credit quality. Deferred conditional variable remuneration plan and linked to objectives (2018) Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2018 [Member] Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2018 Changes in the fair value of equity instruments measured at fair value through other comprehensive income (hedging instrument) Changes In The Fair Value Of Equity Instruments Measured At Fair Value Through Other Comprehensive Income (Hedging Instrument) Changes In The Fair Value Of Equity Instruments Measured At Fair Value Through Other Comprehensive Income (Hedging Instrument) Public sector Public Sector [Member] This member stands for Public sector customers. Repaid by Banco Santander S.A. in May 2024 Repaid By Banco Santander S.A. In May 2024 [Member] Repaid By Banco Santander S.A. In May 2024 Insurance contracts linked to pensions (note 14) Fair value of insurance contracts linked to pensions at beginning of year Fair value of insurance contracts linked to pensions at end of year Insurance Contracts Linked To Pensions Insurance contracts linked to pensions Disclosure of subsidiaries [table] Disclosure of subsidiaries [table] Schedule of list of offshore territories Disclosure Of Detailed Information On Offshore Territories [Table Text Block] Disclosure Of Detailed Information On Offshore Territories Maximum number of active countries with One Common Mobile Experience Deferred Variable Remuneration, Milestone, One Common Mobile Experience, Maximum Number Of Active Countries Deferred Variable Remuneration, Milestone, One Common Mobile Experience, Maximum Number Of Active Countries Title and Position [Axis] Title and Position [Axis] Increase in fair value assets due to changes in inputs Increase in fair value measurement due to change in multiple unobservable inputs to reflect reasonably possible alternative assumptions, assets FINANCIAL LIABILITIES AT AMORTIZED COST Financial liabilities at amortized cost Financial liabilities at amortised cost Changes in value recognised in equity Increase (Decrease) Through Changes In Value Recognized In Equity, Provisions Increase decrease in provisions due to changes in value recognised in equity. Interest rate options Liabilities Under Insurance Contracts [Member] This member stands for liabilities under insurance contracts. Gains (losses) on noncurrent assets held for sale not classified as discontinued operations Gains (Losses) On Noncurrent Assets Held For Sale Not Classified As Discontinued Operations Gains (Losses) On Noncurrent Assets Held For Sale Not Classified As Discontinued Operations Loan-to-value (LTV) ratio Loan To Value Ratio The ratio, expressed as a percentage, of a loan to the value of an asset purchased. Other assets Disclosure of other assets [text block] HKD/EUR Hong Kong, Dollars And Euro [Member] Hong Kong, Dollars And Euro Retrospective application and retrospective restatement [axis] Retrospective application and retrospective restatement [axis] Accrued interest Interest payable Fondo de Titulización, Santander Consumo 8 Santander Consumo 8, F.T. [Member] Santander Consumo 8, F.T. Central government Central Government [Member] This member stands for central government. Disclosure of Debt Instruments [Abstract] Disclosure Of Debt Instruments [Abstract] Disclosure of Debt Instruments [Abstract] Schedule summarising shares assigned for deferred variable remuneration plans Disclosure Of Shares Assigned Between Related Parties, Remuneration, Deferred Variable Remuneration Plans [Table Text Block] Tabular disclosure of shares assigned between the entity and its related parties for deferred variable remuneration plans. Ana Botina and Jose Antonio Alvarez Ana Botin-Sanz de Sautuola y O'Shea And Jose Antonio Alvarez [Member] Ana Botin-Sanz de Sautuola y O'Shea And Jose Antonio Alvarez Cash inflows High-Quality Liquid Assets, Cash Inflow High-Quality Liquid Assets, Cash Inflow Dividend exemption, generating potential tax credit Tax Credit For Taxes Paid Abroad, Threshold Amount Of Exempt Dividends The amount of dividends paid to shareholders of the entity that are exempt from tax, such that taxes paid by the entity in respect of withholdings that exceed such amount, entitle the shareholders to tax credit. Schedule of tax recognized in equity Disclosure Of Income Tax Components Of Other Comprehensive Income [Table Text Block] The disclosure of tax recognized in consolidated equity. Deferred payment, sustainability objective, weight Variable Remuneration, Deferred Payment, Sustainability Objective, Weight Variable Remuneration, Deferred Payment, Sustainability Objective, Weight Net loan-loss provisions Net loan-loss provisions Net Loan-Loss Provision Net Loan-Loss Provision Type of measurement of expected credit losses [domain] Type of measurement of expected credit losses [domain] Provisions for employment-related proceedings (Brazil) Provisions For Labour Proceedings [Member] Provisions For Labour Proceedings Deposits from central banks and credit institutions Disclosure of deposits from banks [text block] Changes in the fair value of equity instruments measured at fair value through other comprehensive income Other comprehensive income, before tax, gains (losses) from investments in equity instruments Credit entities Credit Entities [Member] Credit Entities [Member] Property, plant and equipment Carrying amount Premises and equipment, net Property, plant and equipment including right-of-use assets Increase in profit due to reasonably possible increase in designated risk component Increase (Decrease) In Profit And Loss Due To Reasonably Possible Increase In Designated Risk Component The increase (decrease) in profit and loss as a result of an increase in a designated risk component that was reasonably possible at the end of the reporting period. Excludes defined benefit plan obligations. Financial liabilities, at fair value Liabilities at beginning of period Liabilities at end of period Financial liabilities, at fair value Real estate guarantee Real Estate Guarantee [Member] This member stands for real estate guarantees. NON-CURRENT ASSETS HELD FOR SALE Total non-current assets held for sale Non-current assets or disposal groups classified as held for sale One year to five years Later than one year and not later than five years [member] Financial assets (as a percent) Financial Assets, Percentage Financial assets expressed as a percentage. Percentage of weightings associated with the macroeconomic scenarios Percentage Of Weightings Associated With Macroeconomic Scenarios Represents the percentage of weightings associated with the macroeconomic scenarios. Marketable debt securities Debt Instruments [Member] This member stands for the amount of bonds and other debt represented by marketable securities, other than those having the substance of subordinated liabilities (amount of the loans received, which for credit priority purposes are after common creditors, and includes the amount of the financial instruments issued by the entity which, having the legal nature of capital, do not meet the requirements to qualify as equity, such as certain preferred shares issued). This item includes the component that has the consideration of financial liability of the securities issued that are compound financial instruments. Continuing operations, unless line item indicates otherwise [member] Continuing operations, unless line item indicates otherwise [member] Valuation techniques used in fair value measurement [domain] Valuation techniques used in fair value measurement [domain] Disclosure of detailed information about hedged items [table] Disclosure of detailed information about hedged items [table] Redemptions and repurchases Settlements, fair value measurement, liabilities Maximum Max Top of range [member] Polish zloty Poland, Zlotych Capital conservation buffer, percentage Common Equity Capital Conservation Buffer Percentage Percentage of Common Equity Capital required to be maintained to avoid breaches of minimum capital requirements, as defined by regulatory framework. Pension funds Portfolio And Other Management Fee Income, Pension Funds The amount of income recognised from portfolio and other management fees from pension funds. Financial guarantees and other commitments Assigned Third Party Commissions Expense, Financial Guarantees And Other Commitments Assigned Third Party Commissions Expense, Financial Guarantees And Other Commitments Fixed Income Assets Fixed Income Assets [Member] Fixed Income Assets Scenario [Axis] Scenario [Axis] Hedging instruments (items not designated) Income tax relating to hedges of net investments in foreign operations included in other comprehensive income Insurance premiums paid Decrease Through Insurance Premiums Paid, Provisions Decrease Through Insurance Premiums Paid, Provisions Condensed statements of comprehensive income Condensed Statement of Comprehensive Income [Table Text Block] Other Fee And Commission Income, Other [Abstract] n/a. Variable subject to long-term objectives in cash Cash  payment Key Management Personnel Compensation, Variable Cash-Based Long-Term Employee Benefits The amount of variable cash-based compensation to key management personnel in the form of other long-term employee benefits. Schedule of maturity profile of hedging instruments and average interest and exchange rate by maturity Disclosure of information about terms and conditions of hedging instruments and how they affect future cash flows [text block] Non-financial services Non-Financial Services Other Expense Operating The amount of non-financial services operating expense that the entity does not separately disclose in the same statement or note. Diluted earnings (loss) per share from discontinued operations (in euro per share) Diluted earnings (loss) per share from discontinued operations Increase (decrease) attendance fees (in percentage) Increase (Decrease) Key Management Personnel Compensation, Attendance Fees, Percentage Increase (Decrease) Key Management Personnel Compensation, Attendance Fees, Percentage Other companies Aggregated individually immaterial associates [member] Central banks and credit institution deposits Interest Expense On Liabilities Due To Central Banks And Credit Institutions Deposits Interest Expense On Liabilities Due To Central Banks And Credit Institutions Deposits Retail Banking segment Retail Banking Segment [Member] Information pertaining to the Retail Banking (formerly Commercial Banking) segment. This covers all customer banking businesses, including consumer finance, except those of corporate banking, which are managed through the CIB, and asset management and private banking, which are managed by Wealth Management. The results of the hedging positions in each country are also included, conducted within the sphere of each one's Assets and Liabilities Committee Items that will not be reclassified to profit or loss Other comprehensive income that will not be reclassified to profit or loss, net of tax Risk management and control model, number of lines of defense Risk Management And Control Model, Number Of Lines Of Defense The number of lines of defense which form the base of the risk management and control model. Number of offices Number Of Offices The number of offices. Metrovacesa, S.A. Metrovacesa S.A. [Member] Represents information pertaining to Metrovacesa, S.A. Statement of changes in total equity Description Of Accounting Policy For Changes In Equity, Policy [Policy Text Block] The description of the entity's accounting policy for changes in equity. Eligible preference shares and participating securities Subordinated Liabilities, Preference Shares And Preferred Securities The amount of liabilities for preference shares and preferred securities that are subordinate to other liabilities with respect to claims. Deferred variable remuneration, five-year plan Deferred Variable Compensation Plan Multiannual Objectives, Five Year Plan [Member] Deferred Variable Compensation Plan Multiannual Objectives, Five Year Plan Deferred variable remuneration, four-year plan Deferred Variable Compensation Plan Multiannual Objectives, Four Year Plan [Member] Deferred Variable Compensation Plan Multiannual Objectives, Four Year Plan Revaluation losses Reserve Of Losses On Remeasuring Financial Assets At Fair Value With Changes In Other Comprehensive Income A component of equity representing accumulated losses on remeasuring available-for-sale financial assets. Former executive vice presidents Former Executive Vice Presidents [Member] This member represents former executive vice presidents. Net increase/(decrease) in operating liabilities Net increase/decrease in operating liabilities Adjustments For Increase Decrease In Operating Liabilities Adjustments for increase (decrease) in operating liabilities to reconcile profit (loss) to net cash flow from (used in) operating activities. Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount [axis] Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount [axis] Segment Items [Axis] Segment Items [Axis] Segment Items Present value of the obligations Present value of the obligations Defined benefit obligation, at present value Other related parties Other related parties [member] Currency risk Currency risk Exchange rate Currency risk [member] Net impairment losses for the year Impairment losses charged to income for the year Impairment losses charged to income for the year Impairment loss (reversal of impairment loss) recognised in profit or loss Securitized loans retained on the balance sheet Assets that entity continues to recognise Pensionable base, percent of average last three variable renumeration amounts used in determination Defined Benefit Obligation, Pensionable Base, Percent Average Of Last Three Variable Remuneration Amounts Defined Benefit Obligation, Pensionable Base, Percent Average Of Last Three Variable Remuneration Amounts Non-current assets held for sale and associated liabilities Purchase Of Non-Current Assets And Liabilities Classified As Held-For-Sale Purchase Of Non-Current Assets And Liabilities Classified As Held-For-Sale Other American countries Rest of America Other American Countries [Member] Other American Countries. Decrease in fair value assets due to changes in inputs Decrease in fair value measurement due to change in multiple unobservable inputs to reflect reasonably possible alternative assumptions, assets Shareholder remuneration system and earnings per share Shareholder Remuneration System And Earnings Per Share [Abstract] No definition available. Santander Group UK Santander Group UK [Member] Santander Group UK Release Decrease Through Release Of Extraordinary Provisions Release of extraordinary provisions. Remuneration of key personnel Director Remuneration [Abstract] No definition available. OTHER RECOGNISED INCOME AND EXPENSE OTHER RECOGNISED INCOME AND EXPENSE Other comprehensive income Classes of liabilities [axis] Classes of liabilities [axis] Transfers out of Level 3 of fair value hierarchy, assets Transfers out of Level 3 of fair value hierarchy, assets Executive directors and members of identified staff with total variable remuneration specified amount Executive Directors And Members Of Identified Staff With Total Variable Remuneration Specified Amount [Member] Represents executive directors and members of the Identified Staff with specified total variable remuneration. Types of share-based payment arrangements [axis] Types of share-based payment arrangements [axis] Life insurance, amount Commitments made on behalf of entity, related party transactions Depreciation and amortisation cost Adjustments for depreciation and amortisation expense Property assets from home purchase mortgage loans to households Mortgages Home Purchase Loans [Member] This member stands for a class of financial assets that represents loans to finance the purchase of a home. Issuance of ordinary shares Issue of equity Schedule of undiscounted contractual maturities of financial liabilities at amortized cost by maturity Schedule Of Undiscounted Contractual Maturities Of Financial Liabilities At Amortized Cost By Maturity [Table Text Block] The disclosure of undiscounted contractual maturities of financial liabilities at amortized cost. Pessimistic scenario  Pessimistic Scenario [Member] Represents information pertaining to pessimistic scenario. Other fees and commissions Other Fee And Commission Income, Other Fees And Commissions The amount of other fee and commission income from other fees and commissions. Changes in property, plant and equipment [abstract] Changes in property, plant and equipment [abstract] Asset management Brokerage Fee Income Asset Management The amount of income recognised for brokerage fees charged by the entity for income asset management. Net pension plan assets (note 25) Net defined benefit asset Disclosure of changes in tangible assets in the consolidated balance sheets Disclosure Of Changes In Tangible Assets [Table Text Block] The tabular disclosure of changes in tangible assets. Interest cost (net) Defined Benefit Plans, Interest Expense Net Amount of interest expense net recognized related to defined benefit plan. Investment funds Portfolio And Other Management Fee Income, Investment Funds The amount of income recognised from portfolio and other management fees from investment funds. Deferred tax asset recovery period Remaining Recovery Period Of Deferred Tax Assets For Temporary Differences The remaining recovery period of deferred tax assets for temporary differences. Long-service bonuses and other benefits Defined Benefit Obligation Of Long-Service Bonuses And Other Benefits At Present Value The present value, without deducting any plan assets, of expected future payments required to settle the obligation of long-service bonuses and other benefits resulting from employee service in the current and prior periods. SHAREHOLDERS´ EQUITY Equity Attributable To Owners Of Parent Excluding Accumulated Other Comprehensive Income The amount of equity attributable to the owners of the parent excluding accumulated other comprehensive income and non-controlling interest. Plan assets as a percentage of total plan assets Plan Assets Allocation Percentage Plan assets as a percentage of total plan assets. Increase or decrease on obligations if decrease in actuarial assumption (as a percent) Increase (Decrease) In Benefit Obligation Due To Reasonably Possible Decrease In Actuarial Assumption Percentage increase decrease in benefit obligations due to reasonably possible decrease in actuarial assumption. "Large Exposures" Customers Large Exposure Customers [Member] This member stands for a customer or group of customers that meet the definition of "Large Exposure" as defined by CRR (Regulation(EU) No 575/2013). Discounted Cash Flows on credit spread Flow Discounting Method On Credit Spread [Member] Flow Discounting Method On Credit Spread From A+ to BB From A+ To BB [Member] From A+ To BB Reclassification no-current asset held for sale Increase (Decrease) Through Classified As Held For Sale, Deferred Tax Asset Increase (Decrease) Through Classified As Held For Sale, Deferred Tax Asset Cash flow hedge/currency translation reserve - Continuing hedges Cash Flow Reserves Or Conversion Reserves, Continuing Hedges A component of equity representing the reserve of cash flow hedges and reserve of exchange differences on translation in relation to continuing hedges. Currency swap contract Currency swap Currency swap contract [member] Inheritance trust Inheritance Trust [Member] Inheritance Trust Issued capital Disclosure of issued capital [text block] Number of active customers using Pago Nxt Deferred Variable Remuneration, Milestone, Pago Nxt, Number Of Active Customers Deferred Variable Remuneration, Milestone, Pago Nxt, Number Of Active Customers Difference (assets less liabilities) Certain Financial Assets (Liabilities) Represents the amount of certain financial assets less financial liabilities at amortised cost. Subsidiaries [domain] Subsidiaries [domain] Disclosure of main credit risk aggregates arising on customer business Disclosure of credit risk exposure [text block] Distribution of Banco Santander's profit, shareholder remuneration scheme and earnings per share Disclosure Of Shareholder Distribution Shareholder Remuneration And Earnings Per Share [Text Block] Disclosure of distributions of profit, shareholder remuneration and earnings per share. Other central government Other Central Government [Member] This member represents other central governments. Other subsidiaries Other foreign subsidiaries Other Foreign Countries Not Including UK [Member] This member stands for other foreign countries other than Spain and U.K. Gains (losses) on disposals of non-current assets [abstract] Gains (losses) on disposals of non-current assets [abstract] Total Key management personnel compensation, other long-term employee benefits Customer deposits Disclosure of deposits from customers [text block] Per diems and travel expenses Travel expense Gains Or Losses On Assets Held For Sale [Table] Disclosure Of Gains (Losses) On Assets Held For Sale [Table] Schedule reflecting gains or losses on assets held for sale not classified as discontinued operations. Coming from collection and payment services Credit-related fee and commission income By-law stipulated emoluments Key Management Personnel Compensation, By-Law Stipulated Emoluments The amount of by-law stipulated emolument compensation, which includes both annual emoluments and attendance fees and commissions, to key management personnel. Addition Increase Through Addition Of Extraordinary Provisions Additions of extraordinary provisions. Gains or losses on financial assets and liabilities Disclosure of financial instruments [text block] Loans and advances - credit institutions and customers Loans And Advances, Credit Institutions And Customers [Member] This member represents the loans and advances made to credit institutions and to customers. Entities for sale (Notes 3 y 12) Investment Accounted For Using Equity Method, Transfers To Non Current Assets, Entities For Sale Investment Accounted For Using Equity Method, Transfers To Non Current Assets, Entities For Sale Releases Reversal of impairment loss recognised in profit or loss, property, plant and equipment Classes of intangible assets and goodwill [domain] Classes of intangible assets and goodwill [domain] Carrying amount - Assets Hedging instrument, assets Amounts transferred to initial carrying amount of hedged items Reclassification To Initial Carrying Amount Of Hedged Items Reclassification To Initial Carrying Amount Of Hedged Items ASSETS UNDER REINSURANCE CONTRACTS Reinsurance contracts held that are assets Other additions arising from insurance contracts linked to pensions Increase (Decrease) Through Other Additions Arising From Insurance Contracts Linked To Pensions, Provisions Other additions of provision arising from insurance contracts linked to pension. Assets under management and investment and pension funds managed by the Group Assets Under Management, Policy [Policy Text Block] The description of the entity's accounting policy for assets under management and investment and pension funds. Credit Default Models Credit Default Models [Member] Credit Default Models AUD/EUR Australia, Dollar And Euro [Member] Australia, Dollar And Euro Disclosure of detailed information about intangible assets [line items] Disclosure of detailed information about intangible assets [line items] Projected period Period Over Which Management Has Projected Cash Flows The period over which management has projected cash flows based on financial budgets/forecasts approved by management including, when a period greater than five years is used for a cash-generating unit (group of units). Percentage of equity interests held by significant shareholders Percentage Of Equity Interests Held By Significant Shareholders Percentage Of Equity Interests Held By Significant Shareholders Other Other Provision [Member] This member stands for other provisions. Associated entities Investments in associates accounted for using equity method Depreciation variation (as a percent) Percentage Of Reasonably Possible Depreciation Of Entity's Functional Currency The reasonably possible percentage of the depreciation of entity's functional currency used to determine effect on the consolidated equity. Interest rate futures Interest Rate Futures [Member] This member stands for interest rate futures. Definitions and classification of financial instruments Description of accounting policy for financial instruments [text block] Change in provision assuming 100bp increase in GDP growth rate (as a percent) Percent Change In Provision Assuming 100 Basis Point Increase In GDP Growth Rate Percent Change In Provision Assuming 100 Basis Point Increase In GDP Growth Rate Amount of CVA Accumulated increase (decrease) in fair value of financial assets designated as measured at fair value through profit or loss, attributable to changes in credit risk of financial assets Amounts transferred to income statement Amounts transferred to income statement Reclassification adjustments on exchange differences on translation of foreign operations, before tax Deferred taxes (Charge)/Credit to income Deferred tax expense (income) recognised in profit or loss Accumulated retained earnings Retained earnings, excluding profit (loss) for reporting period [member] Financial guarantees granted and Others Contingent Liabilities And Others Related Party Transactions The amount of contingent liabilities and other resulting from related party transactions. Changes in fair value recognized in profit or loss Gains (losses) recognised in profit or loss including exchange differences, fair value measurement, liabilities Reclassification no-current asset held for sale Increase (Decrease) Through Classified As Held For Sale, Deferred Tax Liability (Asset) Increase (Decrease) Through Classified As Held For Sale, Deferred Tax Liability (Asset) HKD Hong Kong, Dollars Santander Consumer Finance Group Santander Consumer Finance Group [Member] Santander Consumer Finance Group Mortgage-backed bonds loan-to-value ratio for other assets loans (as a percent) Mortgage Backed Bonds Loan To Value Ratio Other Assets Loans Represents the required loan-to-value ratio for mortgage-backed bonds for other assets loans. Completed buildings Completed Buildings [Member] This member stands for construction and property development loans related to completed buildings. Average number of employees with disabilities Average Number Of Employees With Disabilities The average number of employees by disabilities, distributed by professional categories the entity during a period. Other global result Other Global Result Other Global Result Financial assets at fair value through profit or loss Adjustments for decrease (increase) in financial assets measured at fair value through profit or loss Changes in the consolidation method (Note 3) Changes In Scope Of Consolidation Changes In Scope Of Consolidation Swaptions Swaptions [Member] Swaptions Disclosure of transactions between related parties [table] Disclosure of transactions between related parties [table] Additions charged to income Increase (Decrease) Through Additions Charged (Reversed) To Income, Provisions Additions charged or reversed to income for provisions. Other operating expenses Other operating expenses Other operating expense Non-interest expense Other Operating Expense The amount of operating expense that the entity does not separately disclose in the same statement or note. Amount of shares to be transferred by trustee (in shares) Legal Proceedings, Amount Of Shares To Be Transferred By Trustee Legal Proceedings, Amount Of Shares To Be Transferred By Trustee Charge for the year Depreciation, property, plant and equipment Types of hedges [axis] Types of hedges [axis] Consolidated profit (loss) before tax Profit (loss) [abstract] Non-current assets held for sale Non-current assets held for sale Other Comprehensive Income, Before Tax, Non-Current Assets Classified As Held-For-Sale Other Comprehensive Income, Before Tax, Non-Current Assets Classified As Held-For-Sale On-balance-sheet assets On-Balance Sheet Assets [Member] This member represents assets reported on the balance sheet. 2031 to 2035 5 to 10 years Later than five years and not later than ten years [member] Recoveries on loans previously written off Recoveries on loans previously written off Off-balance sheet assets managed by the entity and by joint ventures Off-Balance Sheet Assets Managed By The Entity And By Joint Ventures Represents off-balance sheet assets managed by the entity and by joint ventures. 3 to 5 years Between 3 and 5 years Later than three years and not later than five years [member] Issuance by Banco Santander S.A. in October 2020 Issuance By Banco Santander S.A. In October 2020 [Member] Issuance By Banco Santander S.A. In October 2020 Tangible assets Disclosure of property, plant and equipment [text block] Law 7/2024, Tax Reform Law 7/2024, Tax Reform [Member] Law 7/2024, Tax Reform Contributions to defined contribution pension funds Post-employment benefit expense, defined contribution plans Members of the risk supervision, regulation and compliance committee Risk supervision, regulation and compliance oversight committee Risk Supervision Regulation And Compliance Oversight Committee [Member] This member stands for those persons serving as members of the risk supervision, regulation and compliance oversight committee of the board of directors. Components of equity [domain] Components of equity [domain] Tax Dividend, Cum-ex Transactions Tax Dividend, Cum-ex Transactions [Member] Tax Dividend, Cum-ex Transactions Life Insurance Life Insurance [Member] Life Insurance Dividends Dividends paid in cash Dividends recognised as distributions to owners Disclosure of operating segments [line items] Disclosure of operating segments [line items] 2024 Program 2024 Program [Member] 2024 Program Members of the remuneration committee Remuneration committee Remuneration Committee [Member] This member stands for those persons serving as members of the remuneration committee of the board of directors. Customer deposits Interest expense on deposits from customers Accumulated retained earnings and other reserves Retained earnings and other reserves Retained Earnings And Other Reserves A component of equity representing the entity's cumulative undistributed earnings or deficit and other reserves. Weighted average Average Weighted average [member] Current tax assets Current tax assets Provision used, other provisions Provision used, other provisions Credit cards Credit Cards [Member] Credit Cards Salaries and other remuneration related to retirement Key management personnel compensation, termination benefits Range [domain] Range [domain] Classes of contingent liabilities [axis] Classes of contingent liabilities [axis] Deferred variable remuneration, three-year plan Deferred Variable Compensation Plan Multiannual Objectives, Three Year Plan [Member] Deferred Variable Compensation Plan Multiannual Objectives, Three Year Plan Directors Members of the board of directors Board of directors Director [Member] Interest income Total interest income Interest income Gains Or Losses On Assets Held For Sale [Line Items] Disclosure Of Gains (Losses) On Assets Held For Sale [Line Items] Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. Schedule of movement in hedging components in other comprehensive income Disclosure Of Reconciliation Of Hedging Components In Other Comprehensive Income [Table Text Block] The tabular reconciliation of movement for each hedging component of other comprehensive income. Of which Liberation Amortisation And Impairment, Liberations Intangible Assets Other Than Goodwill The amount of the portion of impairment losses attributable to liberation. Schedule of goodwill assumptions Disclosure of information for cash-generating units [text block] Scenario [Domain] Scenario [Domain] Arbitration matter, amount to be received by entity, interest Arbitration Matter, Amount To Be Received By Entity, Interest Arbitration Matter, Amount To Be Received By Entity, Interest Local sovereign other than official currency risk Local Sovereign Other Than Official Currency Risk [Member] This member stands for local sovereign other than official currency risk. Fidelity bonds, nominal value Nominal Value Of Equity Component Of Convertible Instruments The nominal value of a component of equity representing components of convertible instruments classified as equity. 2025 Program, Second, Capital Released Of Poland Sale 2025 Program, Second, Capital Released Of Poland Sale [Member] 2025 Program, Second, Capital Released Of Poland Sale Retired senior managers Senior Management Retired [Member] This member stands for those persons identified as retired senior management that previously had authority and responsibility for planning, directing and controlling the activities of the entity, directly or indirectly, of that entity. Schedule summarising short-term remuneration (excluding remuneration subject to long-term objectives) Disclosure Of Transactions Between Related Parties, Remuneration, Of Key Personnel Excluding Remuneration For Multi-Annual Objectives [Table Text Block] Tabular disclosure of remuneration of key personnel excluding remuneration tied to multiannual objectives. Homaira Akbari Homaira Akbari Homaira Akbari [Member] Ms. Homaira Akbari [Member] Inflation rate Inflation Rate Inflation Rate Items that may be reclassified to profit or loss ITEMS THAT MAY BE RECLASSIFIED TO PROFIT OR LOSS: Other Comprehensive Income, Items That May Be Reclassified To Profit Or Loss Amount of other reserves that may be reclassified to profit or loss that is attributable to parent. Reverse repurchase agreements Repurchase Agreements Assets [Member] This member stands for financial assets that are repurchase agreements or reverse repurchase agreements. Mortgage Letters Mortgage Letters, Debt Securities [Member] Mortgage Letters, Debt Securities Digital Transformation Award 2022, first block Digital Transformation Award 2022, First Block [Member] Digital Transformation Award 2022, First Block Payments to pensioners and pre-retirees with a charge to internal provisions Decrease Through Payments To Pensioners And Pre Retirees, Provisions Decrease increase in provision balance due to payments to pensioners and pre-retirees. Short positions Short Positions [Member] This member represents the amount of financial liabilities arising from the outright sale of financial assets acquired under reverse repurchase agreements or borrowed. Executive directors Executive Directors [Member] Executive Directors Types of customers [axis] Types of customers [axis] GDP growth Estimation Of Expected Losses, GDP Growth Rate Represents the GDP growth rate percentage in the estimation of expected credit losses. Notional amount Notional amount Liabilities designated at fair value through profit or loss at initial recognition recognised in other comprehensive income Gains (losses) recognised in other comprehensive income on financial liabilities at fair value through profit or loss, designated upon initial recognition or subsequently Unconsolidated structured entities [axis] Unconsolidated structured entities [axis] To stage 1 from stage 2 Increase (Decrease) Through Transfers From Stage 2 To Stage 1 Financial Assets The increase (decrease) in financial assets resulting from transfers from credit risk stage 2 to stage 1. Loan To Value [Domain] Loan To Value1 [Domain] Loan To Value [Domain] Summary of investments by company Disclosure of investments accounted for using equity method [text block] Liabilities relating to insurance contracts measured under PAA Net liabilities or assets for remaining coverage excluding loss component [member] Amounts transferred to income statement Reclassification Adjustments On Hedging Instruments Not Designated, Before Tax Reclassification Adjustments On Hedging Instruments Not Designated, Before Tax Other Other fee and commission income More than 100% LTV More Than 100 Percent [Member] Loan-to-value (LTV) ratio more than 100%. Diluted (in euro per share) Diluted earnings (loss) per share (in euro per share) Diluted earnings (loss) per share Maturity [domain] Maturity [domain] Financial assets with contractual cash flows modified during reporting period while loss allowance measured at lifetime expected credit losses Financial assets with contractual cash flows modified during reporting period while loss allowance measured at lifetime expected credit losses, amortised cost before modification Categories of financial liabilities [axis] Categories of financial liabilities [axis] Residential Residential Property Collateral [Member] This member stands for collateral in the form of residential property. Financial assets held for trading and Financial assets designated as FV with changes in results Financial Assets Held For Trading And Financial Assets Designated At Fair Value Through Profit Or Loss [Member] This member stands for financial assets held for trading and financial assets designated at fair value through profit or loss. Market comparable prices Market comparable prices [member] Investments in Group companies Investments In Group Companies [Member] This member stands investments in Group companies. NZD/EUR New Zealand Dollar And Euro [Member] New Zealand Dollar And Euro Tier 1 phase in capital ratio Level 1 capital coefficient (TIER1) IFRS Tier One Risk Based Capital To Risk Weighted Assets Tier 1 capital divided by risk weighted assets as defined by international regulations. Schedule of effect on fair value of financial instruments classified as Level 3 of a reasonable change in the assumptions used in the valuation Disclosure Of Significant Unobservable Inputs Used In Fair Value Measurements Of Assets And Liabilities [Table Text Block] The disclosure of significant inputs for which market data are not available and that are developed using the best information available about the assumptions that market participants would use when measuring the fair value of assets and liabilities. Disclosure of associates [line items] Disclosure of associates [line items] Liabilities secured by other mortgage securities Liabilities Secured By Non-Asset-Backed Securities The amount of liabilities that are secured by non-asset-backed securities held by the entity. Amounts transferred to income statement Reclassification adjustments on cash flow hedges, before tax Interest rate, spread VaR Interest Rate Interest Rate And Credit Spread Risk [Member] This member stands for the type of risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in market interest rates or credit spread. Fee and commission expense [abstract] Fee and commission expense [abstract] Interest expense Interest expense Interest expense Disclosure of geographical areas [line items] Disclosure of geographical areas [line items] Taxes other than income tax Tax expense other than income tax expense Percentage of loans covered by specific allowance Loans And Receivables, Percentage Covered By Specific Allowances The percentage of loans covered by specific allowances. Gains/losses on financial assets and liabilities and others Gains Losses On Financial Assets And Liabilities And Others, Related Party Transactions The amount of gains or losses on financial assets and liabilities and others attributable to related party transactions. JPY/EUR Japan, Yen And Euro [Member] Japan, Yen And Euro Impairment losses Impairment loss recognised in profit or loss, intangible assets other than goodwill Disclosure of detailed information about business combination [line items] Disclosure of detailed information about business combination [line items] Schedule of gains or losses on non-current assets held for sale that were not classified as discontinued operations Schedule Of Gains (Losses) On Disposal Of Non-Current Assets Held For Sale Not Classified As Discontinued Operations [Table Text Block] Tabular information on gains or losses on non-current assets held for sale that were not classified as discontinued operations. Permanent differences and other Tax Effect Of Expense Not Deductible And Other In Determining Taxable Profit (Tax Loss) Tax Effect Of Expense Not Deductible And Other In Determining Taxable Profit (Tax Loss) Carlos Barrabés Juan Carlos Barrabés Cónsul [Member] Juan Carlos Barrabés Cónsul To voluntary reserves Increase (decrease) through appropriation of retained earnings, equity Assets and liabilities [domain] Assets and liabilities [domain] Amount of sons involved in testamentary trust Legal Proceedings, Number Of Sons Involved In Testamentary Trust Legal Proceedings, Number Of Sons Involved In Testamentary Trust Fx Swap Foreign Exchange Swap [Member] Foreign Exchange Swap Less than 80% IFRS LTV Less Than 80 Percent [Member] Loan-to-value (LTV) ratio less than 80%. Element name and standard label in LTV Greater Than [low end numeric value] Percent [Member] or LTV Less Than [high end numeric value] Percent [Member] formats. Condensed Cash Flow Statement [Table] Condensed Cash Flow Statement [Table] Net loans and leases Loans And Leases, Net Loans And Leases, Net 2028 2 to 3 years Later than two years and not later than three years [member] COMPONENTS OF CASH AND CASH EQUIVALENTS AT END OF THE YEAR Cash and cash equivalents [abstract] Gross amount of financial liabilities offset in the balance sheet Gross financial assets set off against financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements Number of standard scenarios defined Liquidity Risk, Number Of Standard Scenarios Defined Liquidity Risk, Number Of Standard Scenarios Defined Measurement of financial assets and liabilities and recognition of fair value changes Description of accounting policy for fair value measurement [text block] Tier 1 Contingently Convertible Preferred Securities Tier One Contingently Convertible Preferred Securities [Member] Tier One Contingently Convertible Preferred Securities Change in provision assuming 100bp decrease in Manheim index (as a percent) Percent Change In Provision Assuming 100 Basis Point Decrease In Manheim Index Percent Change In Provision Assuming 100 Basis Point Decrease In Manheim Index Land Land Loans [Member] This member stands for construction and property development loans related to land. Increase (decrease) due to changes in presentation Increase (Decrease) Due To Changes In Presentation [Member] Increase (Decrease) Due To Changes In Presentation Deferred conditional variable remuneration plan fifth, seventh, eighth, ninth, tenth, and eleventh cycles Deferred Conditional Variable Remuneration Plan Fifth, Seventh, Eighth, Ninth, Tenth, And Eleventh Cycles 2015, 2017, 2018, 2019, 2020 And 2021 [Member] Deferred Conditional Variable Remuneration Plan Fifth, Seventh, Eighth, Ninth, Tenth, And Eleventh Cycles 2015, 2017, 2018, 2019, 2020 And 2021 Mortgage portfolio Mortgage Portfolio [Member] Mortgage Portfolio Treasury shares, number of shares amortized (in shares) Treasury Shares, Number Of Shares Amortized Treasury Shares, Number Of Shares Amortized Openbank Europe Openbank Europe [Member] Openbank Europe, formerly Digital Consumer Bank Europe Chair of the appointments committee Appointments Committee, Chairman [Member] This member stands for the person serving as chairman of the appointments committee of the board of directors. Statement of changes in equity [line items] Statement of changes in equity [line items] Employee contributions deducted from their net monthly pay Voluntary Sharesave Scheme Monthly Employee Contributions Represents the employee contributions deducted from their net monthly pay for the voluntary Sharesave Scheme. Insurance Portfolio And Other Management Fee Income, Insurance The amount of income recognised from portfolio and other management fees from insurance. EUR/AUD Euro And Australian Dollar [Member] Euro And Australian Dollar Ana Botín Ana Botín Ana Botin-Sanz de Sautuola y O'Shea [Member] The member that represents an individual key personnel named Ana Botin-Sanz de Sautuola y O'Shea. Basic earnings (loss) per share from continuing operations (in euro per share) Basic earnings (loss) per share from continuing operations Marketable debt securities Interest Expense On Debt Instruments Issued Marketable Securities The amount of interest expense on debt instruments issued as marketable debt securities. Santander UK plc, February 1996 Issuance By Santander UK PLC In February 1996 [Member] Information pertaining to issuance of preference shares or preferred securities by Santander UK PLC In February 1996. Issued by Public-sector Debt Instruments Issued By Public Sector [Member] This member stands for instruments issued by governments or central banks held by the entity that represent indebtedness. Summary of goodwill of the main investments in joint ventures and associates Disclosure Of Goodwill Of Main Investments In Joint Ventures And Associates [Table Text Block] Disclosure Of Goodwill Of Main Investments In Joint Ventures And Associates Other reclassifications Other Reclassification Adjustments On Financial Assets Measured At Fair Value Through Other Comprehensive Income, Before Tax Other Reclassification Adjustments On Financial Assets Measured At Fair Value Through Other Comprehensive Income, Before Tax Exchange differences and other items Increase (decrease) through net exchange differences, goodwill Disclosure of geographical areas [table] Disclosure of geographical areas [table] Deferred Multiyear Objectives Variable Remuneration Plan Eighth Cycle Deferred Multiyear Objectives Variable Remuneration Plan Eighth Cycle [Member] Deferred Multiyear Objectives Variable Remuneration Plan Eighth Cycle Deferred payment, percentage paid in shares Variable Remuneration, Deferred Payment, Percentage Paid In Shares The percentage of an award granted under a variable remuneration deferred payment plan paid in shares. Statement of financial position [abstract] Balance sheet (condensed) Statement of financial position [abstract] Interest expense Disclosure of interest expense [text block] Discontinued operations Disclosure of discontinued operations [text block] Other operating results Total other operating income and expenses Other operating income (expense) Other interest expense Interest expense on other financial liabilities Cover [Abstract] Maximum Maximum [Member] Dividends paid to minority shareholders Dividends paid to non-controlling interests Decree-Law 9/2024 Decree-Law 9/2024 [Member] Decree-Law 9/2024 Defined benefit plans [axis] Defined benefit plans [axis] Restricted portion of reserves of subsidiaries Reserves Of Subsidiaries, Restricted A component of equity representing the portion of reserves for subsidiaries restricted as to usage. CET objective, target Variable Remuneration, Deferred Payment, CET1 Objective, Target Variable Remuneration, Deferred Payment, CET1 Objective, Target Insurance contracts linked to pensions Disclosure Of Insurance Contracts Linked To Pensions [Text Block] Disclosure of insurance contracts linked to pensions. Schedule of regulatory capital Schedule Of Compliance With Regulatory Capital Requirements Under Banking Regulations [Table Text Block] Tabular disclosure of the capital amounts and ratios as of the balance sheet date, indicating whether the entity or entities are in compliance with regulatory capital requirements. 2024 Program, Second 2024 Program, Second [Member] 2024 Program, Second MEMORANDUM ITEMS: OFF BALANCE SHEET AMOUNTS Exposure to credit risk on loan and credits and guarantees Exposure to credit risk on loan commitments and financial guarantee contracts Exposure to credit risk on loan commitments and financial guarantee contracts Rest of real guarantees Rest Of Real Guarantees [Member] This member stands for the rest of real guarantees. Excludes real estate guarantees. Sales/Settlements Sales, fair value measurement, liabilities Percent awarded in shares Key Management Personnel Compensation, Long Term And Deferred Compensation, Percent Of Total Awarded In Shares Key Management Personnel Compensation, Long Term And Deferred Compensation, Percent Of Total Awarded In Shares Structure Finance Other Fee And Commission Income, Structure Finance Other Fee And Commission Income, Structure Finance Mexican peso Mexico, Pesos Classes of liabilities [domain] Classes of liabilities [domain] Deferred conditional variable remuneration plan and linked to objectives (2020) Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2020 [Member] Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2020 Glenn Hutchins Glenn Hutchins [Member] Glenn Hutchins To current employees Defined Benefit Obligation To Current Employees At Present Value The present value, without deducting any plan assets, of expected future payments required to settle the obligation to current employees resulting from employee service in the current and prior periods. Of which property collateral With mortgage collateral Encumbered assets IFRS Collateral Pledged [Member] Information pertaining to instruments that contain a pledge of specific property to serve as protection against default. Level 1 ordinary eligible capital (EUR million) Common Equity Tier I Common Equity Tier One Capital Required For Capital Adequacy1 Amount of Common Equity Tier 1 Risk-based Capital required to be categorized as adequately capitalized under regulatory framework for prompt corrective action. Also known as "ordinary eligible capital." Summary of criteria used to determine if a financial instrument has increased credit risk Disclosure of credit risk [text block] Less than BBB Less Than BBB Rating [Member] Less Than BBB Rating Foreign currency balance translation differences and other items Income Tax Relating To Components Of Foreign Currency Balance Translation Differences And Other Items The amount of income tax relating to amounts recognized from foreign currency balance translation differences and other items. Deferred payment, TSR objective, weight Variable Remuneration, Deferred Payment, TSR Objective, Weight Variable Remuneration, Deferred Payment, TSR Objective, Weight Introduction, basis of presentation of the consolidated financial statements (consolidated annual accounts) and other information Disclosure of basis of preparation of financial statements [text block] Proportion of ownership interest in associate, sold (in percentage) Proportion Of Ownership Interest In Associate, Sold Proportion Of Ownership Interest In Associate, Sold Santander Insurance, S.L. Santander Insurance, S.L. [Member] Santander Insurance, S.L. Foreclosed properties Foreclosed Properties [Member] Foreclosed Properties [Member] Document Fiscal Period Focus Document Fiscal Period Focus High-quality liquid assets-HQLAs High-Quality Liquid Assets, Adjusted High-Quality Liquid Assets, Adjusted Total for all related parties [member] Total for all related parties [member] TOTAL ASSETS Total assets Total consolidated assets (Total business) Loans and advances to customers Assets Territorial Jurisdiction [Domain] Territorial Jurisdiction [Domain] Territorial Jurisdiction Litigation Case [Domain] Litigation Case [Domain] Revaluation gains (losses) Gains (losses) on exchange differences on translation of foreign operations, before tax Interim dividend Interim Dividend [Member] Interim Dividend Associates [domain] Associates [domain] Amounts used Decrease Through Amounts Used, Provisions Provisions, amount used in the period. Commission income Disclosure Of Fee And Commission Income [Text Block] The disclosure of fee and commission income. Current taxes Current tax expense (income) and adjustments for current tax of prior periods Credit risk Credit risk [member] Investment, Name [Domain] Investment, Name [Domain] Income statement Profit Loss Related Party The profit (loss) before tax expense or income, attributable to related party transactions. Investment property Properties Investment property [member] Issues Issues, fair value measurement, liabilities Valuation of tangible and intangible assets Valuation Of Tangible And Intangible Assets [Member] This member stands for the valuation of tangible and intangible assets. Types of interest rates [axis] Types of interest rates [axis] (-) Treasure shares and own shares financed Treasury Shares, Held And Financed Treasury Shares, Held And Financed Total income Revenue Issuance By Banco Santander S.A. In January 2017 Issuance By Banco Santander S.A. In January 2017 [Member] Issuance By Banco Santander S.A. In January 2017 Schedule of financial instruments at fair value whose measurement was based on internal models (Levels 2 and 3) Disclosure Of Fair Value Of Financial Instruments, Measurement Based On Internal Models [Table Text Block] The disclosure of the fair value of financial instruments whose measurement was based on internal models (Levels 2 and 3). Financial assets designated at fair value through profit or loss Financial assets at fair value through profit or loss Capital Issued capital [member] Repaid By Banco Santander S.A. In December 2025 Repaid By Banco Santander S.A. In December 2025 [Member] Repaid By Banco Santander S.A. In December 2025 Other reserves Other reserves [member] Losses on litigation settlements Losses on litigation settlements Remuneration and other benefits paid to the Bank's directors and senior managers Disclosure of information about key management personnel [text block] Option Option contract [member] Legal case related to tax deductibility of amortization of goodwill arising on acquisition Legal Case Relating To Tax Deductibility Of Amortization Of Goodwill Arising On Acquisition [Member] Legal Case Relating To Tax Deductibility Of Amortization Of Goodwill Arising On Acquisition Compensation received for having waived the death and disability policy Key Management Personnel Directors Compensation Received, Waiving Death And Disability Policy Key Management Personnel Directors Compensation Received, Waiving Death And Disability Policy Written-off assets Decrease Through Writeoff Financial Asset The decrease in financial assets resulting form write-off. [Refer: Financial Asset] Hedging derivatives Disclosure of general hedge accounting [text block] Increase (decrease) through change in equity of subsidiaries, equity Increase (decrease) through change in equity of subsidiaries, equity Subordinated issue, interest rate reprice term Subordinated Issue, Interest Rate Reprice Term Subordinated Issue, Interest Rate Reprice Term Santander Consumer Finance, S.A. Santander Consumer Finance SA [Member] Represents information pertaining to Santander Consumer Finance, S.A., a subsidiary of the entity. Diversification effect Risk diversification effect [member] Maximum achievement ratio Variable Remuneration, Maximum Achievement Ratio Variable Remuneration, Maximum Achievement Ratio Investment in affiliated companies Investments in subsidiaries, joint ventures and associates reported in separate financial statements Other securitised assets Loans Backed By Assets Rather Than Mortgages [Member] This member stands for loans made to customers which are backed by other assets rather than mortgages. America and rest of the world America And Rest Of The World [Member] America And Rest Of The World Subordinated issue, interest rate, UST Subordinated Issue, Interest Rate, UST Subordinated Issue, Interest Rate, UST Dividends distributed and reimbursements of share premium Dividends Paid And Reimbursements Of Share Premium Dividends Paid And Reimbursements Of Share Premium Performing Performing [Member] This member stands for financial instruments measured at amortised cost and not classified as doubtful. These instruments are not in arrears and there is no reasonable doubts as to their repayment under the contractual terms. Financial instruments include, but are not limited to, financing receivables, loans, debt, and investments. Swaps Swap contract [member] Share Premium Abstract Share Premium [Abstract] N/A Change in provision assuming 100bp decrease in housing price change rate (as a percent) Percent Change In Provision Assuming 100 Basis Point Decrease In Housing Price Change Rate Percent Change In Provision Assuming 100 Basis Point Decrease In Housing Price Change Rate To stage 3 from stage 2 To stage 3 from stage 2 Increase (Decrease) Through Transfers From Stage 2 To Stage 3 Financial Assets The increase (decrease) in financial assets resulting from transfers from credit risk stage 2 to stage 3. Equity instruments issued (not capital) Other Equity Instruments Issued [Member] This member stands for other-than-capital instruments, which are a component of total equity. Performing loans, number of days past due criteria Forborne Loans, Performing Criteria, Number Of Days Past Due The maximum number of days past due used as a criteria for performing loans. Right-of-use for operating lease Right-of-use assets [member] Estimates of present value of future cash flows Estimates of present value of future cash flows [member] Credit spread Credit spread, measurement input [member] Risk management Risk Management [Abstract] No definition available. ACCUMULATED RETAINED EARNINGS Retained earnings, excluding profit (loss) for reporting period Type of Compensation [Domain] Type of Compensation [Domain] Type of Compensation [Domain] Weighted average grant-date fair value of options granted (in GBP per share) Weighted average share price, share options granted Provisions or reversal of provisions, net Provisions And Reversal Of Provisions The net amount of provisions and reversal of provisions. Maximum exposure limits based on credit quality Disclosure Of Maximum Exposure Limits Based On Credit Quality [Table Text Block] Disclosure Of Maximum Exposure Limits Based On Credit Quality Disclosure of nature and extent of risks arising from financial instruments [line items] Disclosure of nature and extent of risks arising from financial instruments [line items] All other Auditor's remuneration for other services Other equity instruments and own shares Other Equity Instruments And Own Shares [Abstract] n/a Actuarial gains/(losses) Insurance Contracts Linked To Pensions, Actuarial Gains (Losses) Actuarial gains losses from insurance contracts linked to pensions. Tax matters Disclosure of income tax [text block] Real estate operations in Spain Real Estate Operations In Spain Segment [Member] Information pertaining to the Real Estate Operations in Spain segment, which includes loans to customers engaging mainly in property development, for which a specialised management model is in place, Metrovacesa's real estate assets and the assets of the former real estate fund (Santander Banif Inmobiliario), together with the Group's ownership interest in SAREB and foreclosed assets. Loan loss provisions, net of taxes and minority interest Loan Loss Provisions, Net Of Taxes And Minority Interest Loan Loss Provisions, Net Of Taxes And Minority Interest Pensions Pensions [Member] This member stands for pensions. Corporate Finance Other Fee And Commission Income, Corporate Finance Other Fee And Commission Income, Corporate Finance Other Other Miscellaneous Liabilities Liabilities classified as Other Liabilities, not otherwise specified. Third party debt securities and equity instruments held in custody Third Party Debt Securities And Equity Instruments Held In Custody Third party debt securities and equity instruments held in custody. Condensed Cash Flow Statements, Captions [Line Items] Condensed Cash Flow Statements, Captions [Line Items] FINANCIAL ASSETS AT AMORTIZED COST Financial assets at amortised cost Financial assets at amortised cost Fixed Key Management Personnel Compensation, Short-Term Employee Benefits, Fixed The amount of fixed compensation to key management personnel in the form of short-term employee benefits. Santander UK Group Holdings plc Santander UK Group Holdings PLC [Member] Santander UK Group Holdings PLC Schedule by type of inherent risk of fair value of trading derivatives Disclosure Of Trading Derivatives [Table Text Block] Tabular disclosure by type of inherent risk of fair value of derivatives Schedule of options activity Disclosure of number and weighted average exercise prices of share options [text block] Modification of participation rates Increase (Decrease) In Non-Controlling Interest, Modification Of Participation Rates The increase (decrease) in noncontrolling interest due to modification of participation rates. Level 2 capital coefficient (TIER 2) IFRS Tier Two Risk Based Capital To Risk Weighted Assets Percentage of Common Equity Tier Two Risk-based Capital to total risk-weighted assets, as defined by regulatory framework. PSA Bank Deutschland GmbH PSA Bank Deutschland GmbH [Member] Represents information pertaining to PSA Bank Deutschland GmbH, a subsidiary of the entity. Chair of the responsible banking, sustainability and culture committee Responsible Banking Sustainability And Culture Committee, Chairman [Member] Information pertaining to the Chairman of the Responsible Banking Sustainability and Culture Committee. Orders Credit Related Fee And Commission Income Orders The amount of income recognised from credit-related fees and commissions from orders. Provision for pensions and other obligations post -employments and Other long term employee benefits Provisions For Pensions And Similar Obligations [Member] This member stands for provisions for pensions and similar obligations. SC Germany S.A., Compartment Consumer 2024-1 SC Germany S.A., Compartment Consumer 2024-1 [Member] SC Germany S.A., Compartment Consumer 2024-1 Territorial Jurisdiction [Axis] Territorial Jurisdiction [Axis] Territorial Jurisdiction Schedule of liabilities under insurance contracts and reinsurance assets in the consolidated balance sheets Disclosure of net, gross and reinsurer's share for amounts arising from insurance contracts [text block] The disclosure of the net and gross amounts and the reinsurer's share for amounts arising from insurance contracts. [Refer: Types of insurance contracts [member]] Portion of consideration paid (received) in cash per share Portion Of Consideration Paid (Received) In Cash Per Share Portion Of Consideration Paid (Received) In Cash Per Share Commodities Commodity price risk [member] Accumulated amount of fair value adjustments on the hedged item - Assets Accumulated Fair Value Hedge Adjustment On Hedged Item Recognised As An Asset, Macro And Micro Hedges The accumulated amount of fair value hedge adjustment on a hedged item recognised as an asset. This value includes both macro and micro hedges and is a non-ifrs measurement used by management. Merchant Platform in Germany and Superdigital in Latin America Merchant Platform in Germany and Superdigital in Latin America [Member] Merchant Platform in Germany and Superdigital in Latin America Net trading income Trading income (expense) Tax credits, deferred tax assets not recognized Tax Credits, Deferred Tax Assets Not Recognized Tax Credits, Deferred Tax Assets Not Recognized Share-based payment Increase (decrease) through share-based payment transactions, equity Number of trading sessions Number Of Trading Sessions Prior To Approval Of Scheme Number of trading sessions between prior to the approval of the scheme by UK tax authorities. Basic earnings (loss) per share from discontinued operations (in euro per share) Basic earnings (loss) per share from discontinued operations Schedule of changes in non-controlling interests Disclosure Of Non-Controlling Interest Changes Explanatory [Table Text Block] The disclosure of changes to non-controlling Interest. Loans and advances, customers including provisions for undrawn authorized Loans And Advances, Customers Including Provisions For Undrawn Authorized [Member] Loans And Advances, Customers Including Provisions For Undrawn Authorized Hedges of net investments in foreign operations Net foreign investments hedges Hedges of net investment in foreign operations [member] Other recognised income and expense of investments in subsidiaries, joint ventures and associates Income tax relating to share of other comprehensive income of associates and joint ventures accounted for using equity method that will be reclassified to profit or loss Ownership interest in associate Proportion of ownership interest in associate Disclosure Of Deposits [Line Items] Disclosure Of Deposits [Line Items] Disclosure Of Deposits [Line Items] Committed assets Committed Assets, Including Own Debt Securities Other Than Covered Bonds And Asset Backed Securities Committed Assets, Including Own Debt Securities Other Than Covered Bonds And Asset Backed Securities RON Romania, New Lei Number of subsidiaries tax resident in the UK Number Of Subsidiaries Tax Resident In The UK The number of subsidiaries tax resident in UK. Crest depositary interest, share equivalent (in shares) Crest Depositary Interest, Share Equivalent Number of entity shares equivalent to a Crest Depositary Interest (CDI) listed on the London Stock Exchange. Other operating income and expenses Disclosure of other operating income (expense) [text block] Exchange differences, net Foreign exchange gain (loss) Movement Foreign exchange gain (loss) Technical reports Technical Reports Expense The amount of expense relating to technical reports. Classes of property, plant and equipment [domain] Classes of property, plant and equipment [domain] Entity Address, Country Entity Address, Country Accumulated amount of fair value adjustments on the hedged item - Liabilities Accumulated Fair Value Hedge Adjustment On Hedged Item Recognised As A Liability, Macro And Micro The accumulated amount of fair value hedge adjustment on a hedged item recognised as a liability. This value includes both macro and micro hedges and is a non-ifrs measurement used by management. Disclosure of reconciliation of changes in insurance contracts by remaining coverage and incurred claims [table] Disclosure of reconciliation of changes in insurance contracts by remaining coverage and incurred claims [table] Euro EUR Euro Member Countries, Euro From discontinued operations Profit (Loss) Before Tax From Discontinued Operations Profit (Loss) Before Tax From Discontinued Operations Other purposes Other Other Purposes Loans [Member] This member stands for other purposes loans. Schedule of non-current assets Schedule Of Noncurrent Assets Classified As Held For Sale [Table Text Block] Tabular disclosure related to non-current assets classified as held for sale. Non-current assets or disposal groups classified as held for sale or as held for distribution to owners [abstract] Non-current assets or disposal groups classified as held for sale or as held for distribution to owners [abstract] ICO loans, pandemic ICO Loan, Pandemic ICO Loan, Pandemic Santander Holding USA (ex. Auto) Santander Holding USA Inc [Member] Represents information pertaining to Santander Holding USA, Inc, a subsidiary of the entity. Others Other Valuation Technique [Member] Other Valuation Technique Foreign currency balance translation differences and other items Deferred Tax Expense Tax Liability Income Tax Expense Relating To Components Of Foreign Currency Balance Translation Differences And Other Items The amount of income tax relating to amounts recognized from foreign currency balance translation differences and other items. Other proceeds related to investing activities Other Proceeds Of Cash Classified As Investing Activities Other Proceeds Of Cash Classified As Investing Activities Geographical areas [domain] Geographical areas [domain] Debt instruments at fair value with changes in other comprehensive income Other comprehensive income, before tax, financial assets measured at fair value through other comprehensive income Risk management Disclosure of financial risk management [text block] Digital Transformation Award 2022 Digital Transformation Award 2022 [Member] Digital Transformation Award 2022 Adjustments due to changes in accounting policies Increase (decrease) due to changes in accounting policy [member] Loan Servicing activities Other Fee And Commission Income, Loan Servicing Activies Other Fee And Commission Income, Loan Servicing Activies Other liabilities Disclosure of other liabilities [text block] Santander UK Santander UK Group Santander UK Group [Member] Represents information pertaining to Grupo Santander UK., a subsidiary of the entity. Decrease in non-performing ratio Decrease In Non-Performing Ratio, Percent Decrease In Non-Performing Ratio, Percent Non-Euro Non Euro [Member] Information related to amounts derived from non-euro currencies. Schedule summarising the cash paid for awards Disclosure Of Cash Paid For Vested Shares Assigned Between Related Parties, Remuneration, Deferred Variable Remuneration Plans [Table Text Block] Tabular disclosure of cash paid for vested shares assigned between related parties under deferred variable remuneration plans. Subordinated issue, term Subordinated Issue, Term Subordinated Issue, Term Balance at beginning of year Balance at end of year Reserve Of Hedging Instruments Reserve Of Hedging Instruments Disclosure of credit risk exposure [table] Disclosure of credit risk exposure [table] Off-balance-sheet assets Off-Balance Sheet Assets [Member] This member represents a resource of an entity on an item that is a positive sign of future economic value and financial position that is not recorded on the balance sheet. Accounting policies Disclosure of material accounting policy information [text block] Gain (loss) recognized in profit and loss Gains (Losses) Recognised In Profit Or Loss, Fair Value Measurement The net gains (losses) recognised in profit or loss on the fair value measurement of assets and liabilities. Increase through business combinations, reserves Increase Through Business Combinations, Reserves Increase Through Business Combinations, Reserves OTHER LIABILITIES Other liabilities Other liabilities Other Other liabilities Securities trading Brokerage Fee Income Securities Trading The amount of income recognised for brokerage fees charged by the entity from trading securities. Loans and advances to customers Loans and advances to customers Loans and advances to customers Total Key Management Personnel Compensation, Employee Benefits Key Management Personnel Compensation, Employee Benefits Maximum amount of the actual collateral that can be considered Loans And Receivables, Maximum Amount Of Actual Collateral That Can Be Considered The maximum amount of the actual collateral that can be considered. Debt securities Debt Securities And Loan And Advances [Member] Debt Securities And Loan And Advances Actuarial gains and losses on defined benefit pension plans Actuarial gains and losses on defined benefit pension plans Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans Level 1 additional eligible capital (EUR million) Additional Tier I Tier One Capital In Excess Of Common Equity Tier One Capital The amount by which the company's Common Equity Tier One Capital exceeds the minimum required for capital adequacy purposes. Also known as "additional eligible capital." Segment Items [Domain] Segment Items [Domain] Segment Items [Domain] Actuarial gains or (-) losses on defined benefit pension plans Income tax relating to remeasurements of defined benefit plans included in other comprehensive income Condensed Financial Statements [Table] Condensed Financial Statements [Table] Interest only loans, mortgage portfolio, percentage Interest Only Loans, Mortgage Portfolio, Percentage Interest Only Loans, Mortgage Portfolio, Percentage Items that may be reclassified to profit or loss Other comprehensive income that will be reclassified to profit or loss, net of tax Number of shares outstanding, beginning of period Number of share options outstanding, end of period Number of share options outstanding in share-based payment arrangement Issuance by Banco Santander Brasil in October 2023 Issuance By Banco Santander Brasil In October 2023 [Member] Issuance By Banco Santander Brasil In October 2023 Fondo de Titulización, Santander Consumo 9 Santander Consumo 9, F.T. [Member] Santander Consumo 9, F.T. Valuation techniques used in fair value measurement [axis] Valuation techniques used in fair value measurement [axis] Debt securities issued and subordinated liabilities Interest expense on debt instruments issued AUD/EUR Australian Dollar And Euro [Member] Australian Dollar And Euro Basic earnings per share [abstract] Basic earnings per share [abstract] LIABILITIES AND EQUITY Equity and liabilities [abstract] Financial assets at amortised cost and financial assets at fair value through other comprehensive income Financial Assets At Amortised Cost And Financial Assets At Fair Value Through Other Comprehensive Income, Category [Member] Financial Assets At Amortised Cost And Financial Assets At Fair Value Through Other Comprehensive Income, Category Number of years of compensation subject to conditions of continued service Key Management Personnel Compensation, Other Long-Term Employee Benefits, Conditions Of Continued Service Period The length of time used for determination of fair value of maximum amount of other long-term employee benefits subject to conditions of continued service. Interest income/(charges) Net interest income Interest income (expense) Reverse repurchase agreements Reverse repurchase agreements and cash collateral on securities borrowed Changes in fair value recognized in equity Gains (losses) recognised in other comprehensive income including exchange differences, fair value measurement, assets Fixed Rate Reset Perpetual AT1 Capital Securities Fixed Rate Reset Perpetual AT One Capital Securities [Member] Fixed Rate Reset Perpetual AT One Capital Securities INF option pricing model Inflation Option Pricing Model [Member] Inflation Option Pricing Model Disclosure of maturity analysis for financial assets held for managing liquidity risk [table] Disclosure of maturity analysis for financial assets held for managing liquidity risk [table] Number of global systemically important banks (G-SIBs) Number Of Banks Designated As Global Systemically Important Banks The number of banks designated as global systemically important banks (G-SIBs). Average foreign exchange rate Average foreign exchange rate Interest cost Increase (decrease) in net defined benefit liability (asset) resulting from interest expense (income) Transfers out of Level 3 of fair value hierarchy, liabilities Transfers out of Level 3 of fair value hierarchy, liabilities Germán de la Fuente German De La Fuente Escamilla [Member] German De La Fuente Escamilla Fair value of encumbered collateral received or own debt securities issued Fair Value Of Encumbered Collateral Received Or Own Debt Securities Issued Fair Value Of Encumbered Collateral Received Or Own Debt Securities Issued Derecognition of financial assets and liabilities Description of accounting policy for derecognition of financial instruments [text block] Ordinary activities income Profit (loss) from operating activities Sensitivity analysis, perpetuity growth rate adjustment, decrease (in basis points) Sensitivity Analysis, Perpetuity Growth Rate Adjustment, Decrease Sensitivity Analysis, Perpetuity Growth Rate Adjustment, Decrease Schedule of maturity of estimated benefits payments Disclosure Of Benefits Maturity Schedule [Table Text Block] Schedule of maturity of estimated benefits payments. Total shareholder return (in percentage) Total Shareholder Return, Percentage Total Shareholder Return, Percentage Audit Auditor's remuneration for audit services Entity Address, Address Line One Entity Address, Address Line One Banco Santander - Chile Banco Santander Chile [Member] Represents information pertaining to Banco Santander - Chile, a subsidiary of the entity. Tangible assets Gains (Losses) On Non-Current Tangible Assets The total gain (loss) on noncurrent tangible assets, which includes impairment and gain (loss) on sales. Conversion of active loans from swiss francs to PLN loans Conversion Of Active Loans From Swiss Francs To PLN Loans [Member] Conversion Of Active Loans From Swiss Francs To PLN Loans Schedule of other comprehensive income, that may be reclassified to profit or loss, by type of instrument and geographical origin of the issuer Disclosure Of Other Comprehensive Income By Instrument And Geographic Origin That May Be Reclassified To Profit Or Loss [Table Text Block] The breakdown of other comprehensive income, that may be reclassified to profit or loss, by type of investment and geographical origin of the issuer. Decrease in net issue premium Increase (Decrease) In Net Issue Premium Increase (Decrease) In Net Issue Premium Discontinued operations Discontinued operations [member] Arbitration matter, amount claimed by counterparty Arbitration Matter, Amount Claimed By Counterparty The amount of the claim by the counterparty in the arbitration matter. Consolidated statement of recognised income and expense Description Of Accounting Policy For Recognised Income and Expense, Policy [Policy Text Block] The description of the entity's accounting policy for recognized income and expense. Gains or losses on non-current assets held for sale not classified as discontinued operations Gains or losses on non-current assets held for sale not classified as discontinued operations Gains (Losses) On Non-Current Assets Held For Sale Not Classified As Discontinued Operations Gains (Losses) On Non-Current Assets Held For Sale Not Classified As Discontinued Operations Santander UK plc, October 1995 Issuance By Santander UK PLC In October 1995 [Member] Information pertaining to issuance of preference shares or preferred securities by Santander UK PLC in October 1995. Number of branches resident in off-shore territories Number Of Branches Resident In Off-Shore Territories Number of branches. Debt and equity instruments Debt And Equity Instruments [Member] This member stands for investments in debt and equity instruments. America IFRS America [Member] Information pertaining to region of Latin America. Provisions Disclosure of provisions [text block] Leverage Ratio IFRS Tier One Leverage Capital To Average Assets Tier 1 Leverage Capital divided by average assets as defined by international regulations. Non-performing loans ratio Non-Performing Loans Ratio Non-Performing Loans Ratio Percentage increase (decrease) in cost of credit Percentage Of Increase (Decrease) In Cost Of Credit The percentage of increase in cost of credit. Disclosure of financial assets [table] Disclosure of financial assets [table] OTHER COMPREHENSIVE INCOME OR LOSS Other accumulated comprehensive income Accumulated other comprehensive income Relationship to Entity [Domain] Title and Position [Domain] Transactional deposits (in percentage) Transactional Deposits, Percentage Transactional Deposits, Percentage To stage 3 from stage 1 Increase (Decrease) Through Transfers From Stage 1 To Stage 3 Financial Assets The increase (decrease) in financial assets resulting from transfers from credit risk stage 1 to stage 3. Digital Transformation Award 2025 Digital Transformation Award 2025 [Member] Digital Transformation Award 2025 Changes in the fair value of equity instruments measured at fair value with changes in other comprehensive income Net gains/losses by valuation Reserve of gains and losses from investments in equity instruments Securitized loans and loans and advances to customers Securitized Loans, Loans And Advances To Customers [Member] Securitized Loans, Loans And Advances To Customers Number of priority use cases with machine learning deployment Deferred Variable Remuneration, Milestone, Number Of Priority Use Cases With Machine Learning Deployment Deferred Variable Remuneration, Milestone, Number Of Priority Use Cases With Machine Learning Deployment Redemption of debt securities Repayments of bonds, notes and debentures Maximum exposure, financial instruments not included elsewhere Maximum Exposure To Credit Risk, Other Financial Instruments The amount that best represents the maximum exposure to credit risk without taking into account any collateral held or other credit enhancements (for example, netting agreements that do not qualify for offset in accordance with IAS 32) for financial instruments not included in other disclosures. Post-employment benefit expense in profit or loss, defined benefit plans Post-employment benefit expense in profit or loss, defined benefit plans Additions to provisions for defined benefit pension plans (note 25) Post-employment benefit expense in profit or loss, defined benefit plans Marketable assets Level 2B Marketable Assets Level 2B [Member] Marketable Assets Level 2B Condensed Statement of Income Captions [Line Items] Condensed Statement of Income Captions [Line Items] Contingent liabilities and commitments Commitments And Guarantees Given Provision [Member] This member represents the provision for commitments and guarantees given. Other foreclosed property assets Other Loans [Member] This member stands for loans (other than construction and property development and home purchase loans). Assets And Liabilities Classified As Held For Sale [Line Items] Assets And Liabilities Classified As Held For Sale [Line Items] Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table. Fx option pricing model FX Option Pricing Model [Member] FX Option Pricing Model Expected rate of return on plan assets Expected Rate Of Return On Plan Assets Expected rate of return on plan assets. Disclosure of details of main interest and similar income Disclosure Of Interest Income [Table Text Block] The tabular disclosure of interest income. Deferred variable compensation, first and second portion Deferred Variable Compensation, First And Second Portion [Member] Deferred Variable Compensation, First And Second Portion Disclosure of sensitivity analysis Disclosure Of Macroeconomic Variables, Sensitivity Analysis [Table Text Block] Macroeconomic Variables, Sensitivity Analysis [Table Text Block] Schedule of certain financial assets and liabilities by maturity Disclosure Of Financial Assets And Liabilities Maturity Periods [Table Text Block] The disclosure of certain financial assets and liabilities by maturity. Schedule of the breakdown of the securitized loans Disclosure of transfers of financial assets [text block] Associates And Joint Ventures [Axis] Equity Method Investments [Axis] Equity Method Investments Brazil Brazil BRAZIL Individual objectives, weight Variable Remuneration, Deferred Payment, Individual Objectives Weight Variable Remuneration, Deferred Payment, Individual Objectives Weight Schedule of detail of liability balances measured at fair value through profit or loss Disclosure Of Financial Liabilities At Fair Value Through Profit Or Loss [Table Text Block] Tabular disclosure of financial liabilities measured at fair value through profit or loss. Maximum number of countries with One Common Mobile Experience as top three rated entity Deferred Variable Remuneration, Milestone, One Common Mobile Experience, Top Rated Entities, Mobile Net Promoter, Maximum Number Of Countries Deferred Variable Remuneration, Milestone, One Common Mobile Experience, Top Rated Entities, Mobile Net Promoter, Maximum Number Of Countries Interest income Finance Income, Related Party Transactions The amount of finance income recognized by the entity in related party transactions. Other reclassifications Other Reclassification Adjustments On Exchange Differences On Translation, Before Tax Other Reclassification Adjustments On Exchange Differences On Translation, Before Tax FINANCIAL LIABILITIES DESIGNATED AT FAIR VALUE THROUGH PROFIT OR LOSS Financial liabilities designated at fair value through profit or loss Financial liabilities at fair value through profit or loss, designated upon initial recognition or subsequently, category [member] Deferred payment, TSR objective, number of peer credit institutions Variable Remuneration, Deferred Payment, TSR Objective, Number Of Peer Credit Institutions Variable Remuneration, Deferred Payment, TSR Objective, Number Of Peer Credit Institutions Shares of investment funds Investment funds Investment funds [member] Disclosure of transactions between related parties [line items] Disclosure of transactions between related parties [line items] Disclosure of fair value measurement of assets [line items] Disclosure of fair value measurement of assets [line items] Discounted Cash Flows on interest rate curve Discounted Cash Flows On Interest Rate Curve [Member] Discounted Cash Flows On Interest Rate Curve Administrative expenses, depreciation and amortisation cost Administrative Expenses, Depreciation And Amortisation Cost Administrative Expenses, Depreciation And Amortisation Cost Provision for post-employment defined benefit obligations Provision For Post Employment Defined Benefit Obligations [Member] This member represents the provision for post-employment defined benefit obligations. MEMORANDUM ITEMS Contingent Liabilities And Contingent Commitments [Member] Information pertaining to contingent liabilities and contingent commitments. Santander Bank Polska S.A. Santander Bank Polska SA [Member] Information pertaining to Santander Bank Polska SA. Legal Case Relating To Programa de Integraçao Social And Contribuição para Financiamento da Seguridade Social Legal Case Relating To Programa de Integraçao Social And Contribuição para Financiamento da Seguridade Social [Member] Legal Case Relating To Programa De Integraçao Social And Contribuição Para Financiamento Da Seguridade Social Santander UK plc Santander UK PLC [Member] Represents information related to Santander UK plc, a subsidiary of the entity. Number of payments subject to fulfilment of specific objectives Variable Remuneration, Deferred Bonus, Number Of Payments Subject To Specific Objectives Number of payments subject to fulfilment of specific objectives. Impairment or reversal of impairment at financial assets not measured at fair value through profit or loss and net gains and losses from changes Impairment loss (reversal) Impairment loss (impairment gain and reversal of impairment loss) determined in accordance with IFRS 9 Receivable on demand Receivable On Demand [Member] This member stands for receivable on demand. Chile CHILE Classes of share capital [domain] Classes of share capital [domain] Other gains and other losses Gains (losses) on disposals of other non-current assets Acquisitions (disposals) of companies and capital increases (reductions) Investments In Subsidiaries Joint Ventures And Associates, Acquisitions (Disposals) And Capital Increases (Reductions) Investments In Subsidiaries Joint Ventures And Associates, Acquisitions (Disposals) And Capital Increases (Reductions) USD/CLP United States Dollar And Chile Peso [Member] United States Dollar And Chile Peso Issuance of other financial instruments Issuance Of Other Financial Instruments Issuance Of Other Financial Instruments Variable subject to long-term objectives in RSUs Key Management Personnel Compensation, Variable Share-Based Long-Term Employee Benefits, RSUs Key Management Personnel Compensation, Variable Share-Based Long-Term Employee Benefits, RSUs Argentina ARGENTINA Accumulated fair value hedge adjustment remaining in statement of financial position for hedged item that ceased to be adjusted for hedging gains and losses, assets Accumulated fair value hedge adjustment remaining in statement of financial position for hedged item that ceased to be adjusted for hedging gains and losses, assets Disclosure of transferred financial assets that are not derecognised in their entirety [table] Disclosure of transferred financial assets that are not derecognised in their entirety [table] Amounts transferred to income statement Reclassification adjustments on financial assets measured at fair value through other comprehensive income, before tax Gains or losses on non-trading financial assets and liabilities mandatorily at fair value through profit or loss Gains (losses) on financial assets at fair value through profit or loss, mandatorily measured at fair value Classes of financial liabilities [axis] Classes of financial liabilities [axis] Classes of financial liabilities [domain] Classes of financial liabilities [domain] Variable interest rate Borrowings, adjustment to interest rate basis Negative goodwill recognized in results Gain recognised in bargain purchase transaction Manheim index Estimation Of Expected Losses, Manheim Index Estimation Of Expected Losses, Manheim Index 2025 Program 2025 Program [Member] 2025 Program Other reclassifications Other Reclassification Adjustments On Cash Flow Hedges, Before Tax Other Reclassification Adjustments On Cash Flow Hedges, Before Tax Subsidiaries and other business units Cash flows used in obtaining control of subsidiaries or other businesses, classified as investing activities Gains (losses) recognised in other comprehensive income including exchange differences, fair value measurement, liabilities Gains (losses) recognised in other comprehensive income including exchange differences, fair value measurement, liabilities Number of jurisdictions within EU's blacklist Number Of Jurisdictions Within EU's Blacklist Number Of Jurisdictions Within EU's Blacklist Interest rate, exchange rate Currency And Interest Rate Risk [Member] This member stands for a type of market risk representing the risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in foreign exchange rates and interest rates. Redemption of own equity instruments Payments To Redeem Entity Shares Payments To Redeem Entity Shares Plan assets Plan assets [member] Undiscounted operating lease payments to be received Undiscounted operating lease payments to be received Lease liabilities Lease liabilities Contractual service margin Contractual service margin [member] Sensitivity analysis, cash flow projections, decrease Sensitivity Analysis, Cash Flow Projections, Decrease Sensitivity Analysis, Cash Flow Projections, Decrease Annual benefit increase rate Actuarial Assumption Of Expected Annual Rate Of Benefit Increases Actuarial Assumption Of Expected Annual Rate Of Benefit Increases Bermuda BERMUDA Time frame, historical simulation Time horizon Value at Risk, Confidence Level Time Frame, Historical Simulation The measurement horizon for the calculation of value at risk, i.e., losses per this number of days. Other employees Other Employees [Member] This member represents for other management Schedule of reserves of subsidiaries based on the companies' contribution to the Group Disclosure Of Reserves Of Subsidiaries [Table Text Block] The disclosure of reserves of subsidiaries within Accumulated retained earnings. 2020 variable remuneration Share Based Variable Remuneration Award 2020 [Member] Share Based Variable Remuneration Award 2020 Purchase of treasury shares (in shares) Purchase Of Treasury Shares, Number Of Shares Purchase Of Treasury Shares, Number Of Shares Minimum Minimum [Member] Profit/(loss) from continuing operations Profit (loss) from continuing operations Income/ (charges) for the period from continuing operations Profit (loss) from continuing operations Financial assets held for trading Financial assets at fair value through profit or loss, classified as held for trading, category [member] Purchases /Issuances Purchases, fair value measurement, assets Minimum number of countries with SuperDigital, excluding Brazil Deferred Variable Remuneration, Milestone, Minimum Number Of Countries With SuperDigital, Excluding Brazil Deferred Variable Remuneration, Milestone, Minimum Number Of Countries With SuperDigital, Excluding Brazil Earnings projections based on financial budgets, approve period Recoverable Amounts Of Certain Cash Generating Units, Period Used In Estimate Recoverable Amounts Of Certain Cash Generating Units, Period Used In Estimate Santander Finance Preferred, S.A. (Unipersonal), September 2004 Issuance By Santander Finance Preferred S.A. In September 2004 [Member] Information pertaining to issuance of preference shares or preferred securities by Santander Finance Preferred S.A. In September 2004. Profit (loss) attributable to ordinary equity holders of parent including dilutive effects Profit (loss), attributable to ordinary equity holders of parent entity, used in calculating diluted earnings per share Decrease in losses on litigation settlements Litigation Contingencies, Decrease In Losses On Litigation Settlements Litigation Contingencies, Decrease In Losses On Litigation Settlements Other EU countries Other European Countries [Member] Other European Countries. Risk-weighted assets (EUR million) IFRS Risk Weighted Assets Amount of risk-weighted assets as calculated in accordance with international regulatory capital standards. CAPITAL Capital stock Subscribed capital Share capital Issued capital Assets under management Assets Under Management [Member] This member stands for assets under management. Reserve for retired capital Retired Capital Reserve A component of equity representing reserves for retired capital. Other Other intangible assets [member] 2025 Program, Second 2025 Program, Second [Member] 2025 Program, Second Total Key Management Personnel Compensation, Short-Term And Deferred The amount of compensation to key management personnel in the form of variable cash and share-based payments. Includes both short-term and other long-term employee benefits. Excludes long-term benefits linked to multi-annual objectives. Change in foreign currency exchange rate (as a percent) Foreign Currency Exchange Rate, Change Percentage The percentage change in the foreign currency exchange rate. Transfers between equity items Increase (Decrease) Through Transfers Between Equity Items The increase (decrease) in equity resulting from transfers between equity items. Disclosure of reconciliation of changes in insurance contracts by remaining coverage and incurred claims [abstract] Disclosure of reconciliation of changes in insurance contracts by remaining coverage and incurred claims [abstract] Categories of financial assets [axis] Categories of financial assets [axis] Interest rate options Interest Rate Option [Member] This member stands for an interest rate option. Non-current assets held for sale Non-current assets held for sale [member] Deferred variable in cash Key Management Personnel Compensation, Deferred Cash-Based Short-Term Employee Benefits The amount of deferred cash compensation to key management personnel in the form of short-term employee benefits. Pensionable base, number of variable renumeration amounts used in determination Defined Benefit Obligation, Pensionable Base, Number Of Variable Remuneration Amounts Defined Benefit Obligation, Pensionable Base, Number Of Variable Remuneration Amounts AA IFRS Standard Poors AA Rating [Member] AA credit rating as defined by the external credit rating agency, Standard & Poor's. Other disclosures Disclosure Of Other Information About Financial Assets And Liabilities [Text Block] The disclosure of other financial assets and liabilities. Share capital (in shares) Number of shares outstanding Issuance/Redemption of equity instruments Issuance (Redemption) Of Treasury Shares Issuance (Redemption) Of Treasury Shares Non publicly listed Unlisted [Member] This member stands for equity instruments that are not listed on exchanges. Disclosure of details of fee and commission income Disclosure Of Fee And Commission Income [Table Text Block] The tabular disclosure of fee and commission income. Disclosure of details of income from dividends Disclosure Of Dividends [Table Text Block] The tabular disclosure of dividends. Dividends are distributions of profits to holders of equity investments in proportion to their holdings of a particular class of capital. Products and services [axis] Products and services [axis] Acquisition of own equity instruments Acquisition of own equity instruments Payments To Acquire Entity Shares The cash outflow to acquire entity's shares. Total financial liabilities Financial liabilities Balance at beginning of year Balance at year-end Financial liabilities Net pension assets Net Pension Assets Net Pension Assets Net charges recorded against valuation allowances Noncurrent Assets Held For Sale, Tangible Assets, Valuation Allowance Charges Charges for the period against the valuation allowance for non-current assets held for sale. Hedging derivatives Hedging Derivatives [Member] Hedging Derivatives Tax expense or income from continuing operations Continuing operations Tax on profit Tax expense (income) Tax expense (income) Gain or losses on financial assets and liabilities held for trading, net Gains Losses On Financial Assets And Liabilities Held For Trading Amount of gains or losses on financial assets and liabilities held for trading. Non-deductible provisions Non-Deductible Provisions [Member] This member stands for non-deductible provisions. Disclosure of maturity analysis of operating lease payments [line items] Disclosure of maturity analysis of operating lease payments [line items] Stage 1 12-month expected credit losses [member] Debt-to-income ratio Debt To Income Ratio Measurement of ability to repay debt expressed as a percentage calculated by dividing total recurring month debt by gross monthly income. Treasury shares, number of shares transferred (in shares) Treasury Shares, Number Of Shares Transferred Treasury Shares, Number Of Shares Transferred Schedule of other provisions by geographical area and by type of provision Disclosure of other provisions, contingent liabilities and contingent assets [text block] Citibank Citibank [Member] Citibank Cash equivalents at central banks Cash and bank balances at central banks Administrative expenses Administrative expenses Exchange differences and other movements Subordinated Liabilities, Increase (Decrease) Due To Exchange Differences And Other Movements The increase (decrease) in subordinated liabilities due to exchange differences and other movements. Disclosure of classes of share capital [line items] Disclosure of classes of share capital [line items] Maturity [axis] Maturity [axis] Income tax relating to items that may be reclassified to profit or loss Income tax Income tax relating to components of other comprehensive income that will be reclassified to profit or loss Non-current assets or disposal groups classified as held for sale Non-current assets or disposal groups classified as held for sale [member] United Kingdom United Kingdom UNITED KINGDOM Guernsey GUERNSEY Issuances Additions, Subordinated Liabilities New liabilities assumed during the reporting period that are subordinated to claims of general creditors. Net assets for pensions Net Assets For Pensions Net assets for pensions. Goodwill Goodwill at beginning of period Goodwill at end of period Goodwill Other financial liabilities Others Other Financial Liabilities [Member] This member represents the amount of payment obligations having the nature of financial liabilities not included in other items, and liabilities under financial guarantee contracts, unless they have been classified as non-performing. Consideration (in USD per share) Consideration (in MXN/EUR per share) Consideration Paid (Received), In Cash Per Share Consideration Paid (Received), In Cash Per Share Associates [axis] Associates [axis] Financial assets at amortized cost Gains (losses) on financial assets at amortised cost Schedule of equivalent euro value of assets and liabilities Disclosure Of Equivalent Euro Value Of Assets And Liabilities [Table Text Block] The disclosure of equivalent euro value of assets and liabilities. IFRS Statement [Line Items] Disclosure Of IFRS Statement [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Document Type Document Type Greece GREECE To stage 2 from stage 1 To stage 2 from stage 1 Increase (Decrease) Through Transfers From Stage 1 To Stage 2 Financial Assets The increase (decrease) in financial assets resulting from transfers from credit risk stage 1 to stage 2. Fair value of assets IFRS Assets Fair Value Disclosure The amount of fair value of asset. Spain SPAIN Commission expense Total commission expense Fee and commission expense ICO loans, percentage of total portfolio ICO Loans, Percentage Of Total Portfolio ICO Loans, Percentage Of Total Portfolio Unrestricted reserves Unrestricted Reserves A component of equity representing reserves unrestricted as to usage. Non-performing rate NPL ratio Non-Performing Ratio The percentage of instruments classified as non-performing, calculated as the amount of non-performing loans and advances to customers and non-performing contingent liabilities (without country risk) divided by the amount of total loans and advances to customers and contingent liabilities (without country risk). Discounted cash flows on inflation swap rate Discounted Cash Flows On Inflation Swap Rate [Member] Discounted Cash Flows On Inflation Swap Rate Exchange differences and other Increase (decrease) through net exchange differences, intangible assets other than goodwill (Condensed) income statement Underlying income statement (condensed) Reconciliation of statutory results to underlying results Profit or loss [abstract] Net variation Gross additions Increase (decrease) through transfers, financial assets Digital Transformation Award 2020 Digital Transformation Award 2020 [Member] Digital Transformation Award 2020 From net assets Foreign Exchange Gain (Loss), Net Assets Foreign Exchange Gain (Loss), Net Assets From results Foreign Exchange Gain (Loss), Results Foreign Exchange Gain (Loss), Results Disclosure of financial liabilities [abstract] Designated And Not Designated Items [Domain] Designated And Not Designated Items [Domain] Designated And Not Designated Items [Domain] Trade payables Trade payables Collective calculated Expected credit losses collectively assessed [member] Key management personnel compensation, buyouts and sign-on awards Key Management Personnel Compensation, Buyouts And Sign-On Awards Key Management Personnel Compensation, Buyouts And Sign-On Awards Incorporation of Group companies, net Incorporation of Group companies, net Increase (Decrease) Through Incorporation Of Group Companies, Provisions Increase (Decrease) Through Incorporation Of Group Companies, Provisions Types of share-based payment arrangements [domain] Types of share-based payment arrangements [domain] Refinanced and restructured transactions Refinanced And Restructured Transactions Amount of loans and receivables that are refinanced and restructured. Includes the net balance of the impairment of the accumulated value or accumulated losses in the fair value due to credit risk. Dividend [Domain] Dividend [Domain] Dividend [Domain] Schedule of customer deposits Schedule Of Customer Deposits [Table Text block] The detail, by classification, geographical area and type, of Customer deposits. Components of equity [axis] Components of equity [axis] Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items] Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [line items] Trading Derivatives And Short Positions [Abstract] Trading Derivatives And Short Positions [Abstract] n/a Non-trading financial assets mandatorily at fair value through profit or loss Non Trading Financial Assets At Fair Value Through Profit Or Loss Mandatorily Measured At Fair Value Category [Member] This member stands for the non-trading financial assets mandatorily measured at fair value through profit or loss category. Marketable debt securities Guarantees Disclosure of financial liabilities [line items] Subordinated liabilities [abstract] Subordinated liabilities [abstract] Benefits paid Insurance Contracts Linked To Pensions, Benefits Paid Benefits paid from insurance contracts linked to pensions. Distributable maximum amount Dividends, Maximum Amount Distributable Dividends, Maximum Amount Distributable Other Regions Other Regions [Member] Relates to all other regions in which the entity does business, excluding Spain, UK and Brazil. Santander Consumer USA Holdings Inc. Santander Consumer USA Holdings Inc [Member] Represents information pertaining to Santander Consumer Holdings Inc. (SCUSA). Schedule of changes in provision Disclosure Of Provision Roll Forward [Table Text Block] Disclosure of provision rollforward. Own shares Capital redemption reserve Insured capital of premium contributed, percentage received by beneficiaries Insured Capital of Premium Contributed, Percentage Received by Beneficiaries Insured Capital of Premium Contributed, Percentage Received by Beneficiaries Disclosure of bonds and debentures by currency Disclosure Of Details By Currency Of Issue Of Financial Liabilities Outstanding [Table Text Block] The disclosure detail by currency of issue of financial liabilities outstanding. Issuance By Banco Santander S.A. In April 2016 Issuance By Banco Santander S.A. In April 2016 [Member] Issuance By Banco Santander S.A. In April 2016 Exchange rate options Exchange Rate Option [Member] This member stands for an exchange rate option. Internal provisions for pensions Internal Provisions For Pensions Internal provisions for pensions. Loans and advances to central banks and credit institutions Disclosure of loans and advances to banks [text block] CHF/EUR Switzerland, Francs And Euro [Member] Switzerland, Francs And Euro Sale of interest held, price per share Sale of Interest Held, Price per Share Sale of Interest Held, Price per Share Categories of related parties [domain] Categories of related parties [domain] Grupo PSA Grupo PSA [Member] Represents information pertaining to Grupo PSA. Non-controlling interest, other comprehensive income Non Controlling Interests, Other Comprehensive Income [Member] This member stands for equity in a subsidiary not attributable, directly or indirectly, to the parent representing the amount of accumulated items of income and expense (including reclassification adjustments) that are not recognised in profit or loss. Loans And Advances To Customers Abstract Loans And Advances To Customers [Abstract] n/a EUR/PEN Euro And Peruvian Nuevo Sol [Member] Euro And Peruvian Nuevo Sol Net  additions and disposals Net Additions (Disposals), Intangible Assets Other Than Goodwill The net increase or (decrease) in intangible assets other than goodwill resulting from additions and disposals. Payments to external funds Decrease Through Payments To External Funds, Provisions Payments to external funds. Gains (losses) on net monetary position Gains (losses) on net monetary position Deferred conditional variable remuneration plan fourth and fifth cycles Deferred Conditional Variable Remuneration Plan Fourth And Fifth Cycles 2014 And 2015 [Member] Information pertaining to the Deferred Conditional Variable Remuneration Plan Fourth And Fifth Cycles (2014 and 2015, respectively). Consolidation Items [Domain] Consolidation Items [Domain] Rest of Europe European Union Excluding Spain [Member] European Union Excluding Spain [Member] Schedule of detail of staff costs Disclosure Of Detailed Information About Personnel Expenses Explanatory [Table Text Block] The disclosure of detailed information about personnel expenses. Other comprehensive income or loss Accumulated Other Comprehensive Income Attributable To Non-controlling Interests The amount attributable to non-controlling interest of accumulated items of income and expense (including reclassification adjustments) that are not recognized in profit or loss as required or permitted by other IFRSs. Subordinated Bonds By Issuance [Domain] Subordinated Bonds By Issuance [Domain] Subordinated Bonds By Issuance [Domain] Condensed Balance Sheet Statement [Table] Condensed Balance Sheet Statement [Table] Financial liabilities held-for-trading Adjustments for increase (decrease) in financial liabilities held for trading Schedule of financial liabilities measured at other than fair value Disclosure Of Financial Liabilities Measured At Other Than Fair Value [Table Text Block] The disclosure of financial liabilities measured at other than fair value. Discounted Cash Flows on margin of a reference portfolio Discounted Cash Flows On Margin Of A Reference Portfolio [Member] Discounted Cash Flows On Margin Of A Reference Portfolio Weighted average number of shares outstanding (in shares) Weighted average number of ordinary shares used in calculating basic earnings per share Spanish and foreign government securities Spanish And Foreign Government Securities [Member] This member represents amount of Spanish and foreign government securities. PagoNxt, Nomination Committee PagoNxt, Nomination Committee [Member] PagoNxt, Nomination Committee Subordinated Bonds By Issuance [Axis] Subordinated Bonds By Issuance [Axis] Subordinated Bonds By Issuance Tax Reform [Domain] Tax Reform [Domain] Tax Reform [Domain] Other asset - backed securities personal loans average maturities Other Asset Backed Securities Personal Loans Average Maturity Represents the average maturity for other assets - backed securities personal loans. Schedule of number of offices Disclosure Of Number Of Offices [Table Text Block] The number of offices. Schedule of depreciation rates of tangible assets Disclosure of depreciation and amortisation expense [text block] Total achievement of incentive Key Management Personnel Compensation, Long Term And Deferred Compensation, Percent Of Achievement Key Management Personnel Compensation, Long Term And Deferred Compensation, Percent Of Achievement Contributions made by employees Contributions Made By Employees Contributions made by employees. Subordinated debt Deposits redeemable at notice Subordinated Liabilities [Member] Represents subordinated liabilities. CNP Santander CNP Santander CNP Santander [Member] Santander Insurance [Member] Tier 1 IFRS Common Equity Tier One Capital Amount of Common Equity Tier One Risk-based Capital, as defined by international regulatory framework. Wealth Management & Insurance Wealth Management And Insurance Segment [Member] Wealth Management & Insurance (Wealth): includes the asset management business (Santander Asset Management), the corporate unit of Private Banking and International Private Banking in Miami and Switzerland and the insurance business (Santander Insurance). Schedule of deferred variable remuneration systems Disclosure Of Terms And Conditions Of Deferred Variable Remuneration Plans [Table Text Block] The disclosure of the terms and conditions of deferred variable remuneration plans. Income tax Tax Expense (Income), Including Discontinued Operations Tax Expense (Income), Including Discontinued Operations Santander España Santander Espana [Member] Information pertaining to Santander Espana. Schedule of provision for pensions and similar obligations Disclosure Of Provision For Pensions And Similar Obligations [Table Text Block] Disclosure of Provision for pensions and similar obligations. Earnings/(losses) recognised in another cumulative overall result Earnings (losses) recognized in other comprehensive income Gain (Loss) On Hedging Instrument Recognised In Other Comprehensive Income Gain (Loss) On Hedging Instrument Recognised In Other Comprehensive Income Defined benefit plans [domain] Defined benefit plans [domain] Decrease in portfolio of SMEs Increase (Decrease) In Portfolio Of SME Increase (Decrease) In Portfolio Of SME Number of employees - women Number Of Women Employees The number of personnel, identified as women, employed by the entity at a date. Spain Country of domicile [member] IT equipment and fixtures Computer equipment [member] NET INCREASE/(DECREASE) IN CASH AND CASH EQUIVALENTS Increase (decrease) in cash and cash equivalents after effect of exchange rate changes Cash-generating units information Disclosure of information for cash-generating units [line items] Past service cost Increase (decrease) in net defined benefit liability (asset) resulting from past service cost Deferred conditional variable remuneration plan twelfth cycle Deferred Conditional Variable Remuneration Plan Twelfth Cycle 2022 [Member] Deferred Conditional Variable Remuneration Plan Twelfth Cycle 2022 Getnet Tecnologia Proces S.A. Getnet Tecnologia Proces S.A. [Member] Getnet Tecnologia Proces S.A. Memorandum items: subordinated liabilities Outstanding issue amount Balance at beginning of year Balance at end of year Subordinated liabilities Sovereign risk Sovereign Risk [Member] Credit risk assumed in transactions with the central bank (including the regulatory cash reserve requirement), the issuer risk of the Treasury or similar body (government debt securities) and the risk arising from transactions with public entities that have the following features: their funds are obtained only from fiscal income; they are legally recognized as entities directly included in the central government public sector; and their activities are of a non-commercial nature. Santander Seguros y Reaseguros, Compañía Aseguradora, S.A. Santander Seguros Y Reaseguros Compania Aseguradora SA [Member] Represents information pertaining to Santander Seguros y Reaseguros, Compania Aseguradora, S.A., a subsidiary of the entity. NII risk concentration NII Risk Concentration [Member] This member stands for first risk assumption used in sensitivity analysis. Pessimistic scenario 1 Pessimistic Scenario One [Member] Represents information pertaining to pessimistic scenario one. Issuance By Banco Santander SA In May 2023 Issuance By Banco Santander SA In May 2023 [Member] Issuance By Banco Santander SA In May 2023 C) Designated elements Designated Items [Member] Designated Items 2023 Program 2023 Program [Member] 2023 Program Foreclosed equity instruments Foreclosed Equity Instruments [Member] Foreclosed Equity Instruments [Member] Fair value hedges Fair value hedges [member] Latin America and rest Latin America And Rest Of The World [Member] Latin America And Rest Of The World [Member] Disclosure of concentrations Disclosure of nature and extent of risks arising from financial instruments [text block] 1 to 3 years Between 1 and 3 years Later than one year and not later than three years [member] Schedule of changes in deferred tax assets and liabilities Disclosure of deferred taxes [text block] Notes and other securities Promissory notes and other securities Notes And Other Securities [Member] Represents notes and other securities. Net additions Increase through origination or purchase, financial assets Tier 2 Subordinated Debt Tier 2 Subordinated Debt [Member] Tier 2 Subordinated Debt Consolidated Entities [Domain] Consolidated Entities [Domain] Minimum number of countries with One Common Mobile Experience as top three rated entity Deferred Variable Remuneration, Milestone, One Common Mobile Experience, Top Rated Entities, Mobile Net Promoter, Minimum Number Of Countries Deferred Variable Remuneration, Milestone, One Common Mobile Experience, Top Rated Entities, Mobile Net Promoter, Minimum Number Of Countries Pillar 1 percentage Common Equity Pillar One Capital Ratio Percentage of Common Equity Pillar One Risk-based Capital to total risk-weighted assets, as defined by regulatory framework. Disclosure of classes of share capital [abstract] Disclosure of classes of share capital [abstract] Type of Compensation [Axis] Type of Compensation [Axis] Type of Compensation Underlying results Underlying Profit Items [Member] Underlying Profit Items Expected cost Other Equity Instruments Expected Cost The estimated cost of component of equity representing components of convertible instruments classified as equity. Current Fiscal Year End Date Current Fiscal Year End Date Santander Consumer Bank Polska Santander Consumer Bank Polska [Member] Santander Consumer Bank Polska Schedule of functional breakdown of final employment by gender Disclosure Of Detailed Information About Employee By Gender Explanatory [Table Text Block] The disclosure of detailed information about the functional breakdown of employment by gender. Non-current assets held for sale and liabilities associated with non-current assets held for sale Disclosure Of Noncurrent Assets And Liabilities Or Disposal Groups Classified As Held For Sale [Text Block] Disclosure Of Noncurrent Assets And Liabilities Or Disposal Groups Classified As Held For Sale Exchange differences and other changes Exchange Differences And Other Changes Exchange Differences And Other Changes Ireland IRELAND Disclosure Of Other Comprehensive Income [Abstract] Disclosure Of Other Comprehensive Income CCC and below CCC And Below [Member] CCC And Below Changes in the fair value of financial liabilities at fair value through profit or loss attributable to changes in credit risk Other comprehensive income, net of tax, change in fair value of financial liability attributable to change in credit risk of liability Banco Santander Argentina S.A. Banco Santander Argentina S.A. [Member] Banco Santander Argentina S.A. Subordinated Liabilities, Preference Shares, First Series Subordinated Liabilities, Preference Shares, First Series [Member] Subordinated Liabilities, Preference Shares, First Series Financial instruments credit-impaired Financial instruments credit-impaired [member] Debt securities issued Bonds And Debentures Outstanding And Subordinated Liabilities [Member] Represents bonds and debentures and subordinated liabilities outstanding. "Large Exposures" Customers, top 40 Large Exposure Customers, Top Forty [Member] Large Exposure Customers, Top Forty Preference Shares And Preferred Securities By Issuance [Domain] Preference Shares And Preferred Securities By Issuance [Domain] Preference Shares And Preferred Securities By Issuance [Domain] FINANCIAL LIABILITIES AT AMORTIZED COST Financial liabilities at amortised cost Financial liabilities at amortised cost, category [member] Fair value of investment property Fair value of property, plant and equipment materially different from carrying amount Gina Díez Gina Lorenza Diez Barroso Aracarraga [Member] Gina Lorenza Diez Barroso Aracarraga Other companies and consolidation adjustments Other Companies Exchange Differences And Consolidation Adjustments [Member] Represents information pertaining to other subsidiaries, exchange differences, and consolidation adjustments. Italy ITALY Estimated cost of compensation to shareholders and bondholders applied to the commercial loyalty program Other Equity Instruments, Expected Cost, Allocated To Loyalty Programs Other Equity Instruments, Expected Cost, Allocated To Loyalty Programs Disbursed for payment of civil liability insurance premium Payment Of Civil Liability Insurance Premium The cash outflow for payment of civil liability insurance premium. Condensed Balance Sheet Statements, Captions [Line Items] Condensed Balance Sheet Statements, Captions [Line Items] Loans and advances to customers Disclosure of loans and advances to customers [text block] Total financial assets Financial assets Impairment at beginning of year Impairment at end of year Financial assets at beginning of period Financial assets at end of period Credit impaired loans Financial assets Impairment losses and credit risk allowances. Coverage for unimpaired assets (business in Spain) Financial assets 2025 Program, Second, Group Underlying Profit 2025 Program, Second, Group Underlying Profit [Member] 2025 Program, Second, Group Underlying Profit Other disclosures Other Disclosures [Abstract] No definition available. Sale of proportion of ownership interest in subsidiary Sale Of Proportion Of Ownership Interest In Subsidiary Sale Of Proportion Of Ownership Interest In Subsidiary Reclassification of financial assets at amortized cost Reclassified Financial Assets From Amortized Cost [Member] Reclassified Financial Assets From Amortized Cost Minimum number of active countries with One Common Mobile Experience Deferred Variable Remuneration, Milestone, One Common Mobile Experience, Minimum Number Of Active Countries Deferred Variable Remuneration, Milestone, One Common Mobile Experience, Minimum Number Of Active Countries Schedule of effectiveness of hedging, impacts on profit or loss and other comprehensive income Disclosure of information about amounts that affected statement of comprehensive income as result of hedge accounting [text block] Options granted (in GBP per share) Weighted average exercise price of share options granted in share-based payment arrangement Poland POLAND Provision recognised for non-current assets held for sale Provision Recognised For Non-Current Assets Held For Sale, Tangible Assets Provision Recognised For Non-Current Assets Held For Sale, Tangible Assets Issuance by Banco Santander S.A. in May 2021 Issuance By Banco Santander S.A. In May 2021 [Member] Issuance By Banco Santander S.A. In May 2021 Portugal PORTUGAL Average fixed interest rate Average rate of hedging instrument Schedule of contingent commitments Disclosure of contingent liabilities [text block] Civil engineering construction Civil Engineering Construction Loans [Member] This member stands for civil engineering construction loans. Insurance contracts by remaining coverage and incurred claims [domain] Insurance contracts by remaining coverage and incurred claims [domain] Schedule of details of provisions Disclosure Of Reconciliation Of Provisions [Table Text Block] Disclosure Of Reconciliation Of Provisions Temporary difference, unused tax losses and unused tax credits [domain] Temporary difference, unused tax losses and unused tax credits [domain] Legal case relating to deduction of expenses in income tax Legal Case Relating To Deduction Of Expenses In Income Tax [Member] Legal Case Relating To Deduction Of Expenses In Income Tax Accumulated depreciation Accumulated depreciation and amortisation [member] 2025 variable remuneration Share Based Variable Remuneration Award 2025 [Member] Share Based Variable Remuneration Award 2025 Compensation received as representative from subsidiary Key Management Personnel Directors Compensation Received From Subsidiary The amount of director's compensation received by a related party of the reporting entity from a subsidiary of the reporting entity. Conversion of financial liabilities into equity Increase (decrease) through conversion of convertible instruments, equity EVE risk concentration EVE Risk Concentration [Member] EVE Risk Concentration Increase (decrease) in credit risk (in percentage) Increase (Decrease) In Credit Risk With Customers, Percent The percentage increase in credit risk with customers. 2027 1 to 2 years Later than one year and not later than two years [member] Financial assets at fair value through other comprehensive income and financial assets at amortised cost Financial Assets At Fair Value Through Other Comprehensive Income And Financial Assets At Amortised Cost [Member] Information pertaining to the categories, combined, of financial assets at fair value through other comprehensive income and financial assets at amortised cost. Designated And Undesignated Items [Axis] Designated And Not Designated Items [Axis] Designated And Not Designated Items Shares delivered (immediate payment variable remuneration) (in shares) Number Of Shares Earned In Share-Based Payment Arrangement, Immediate The number of shares earned in a share-based payment arrangement not subject to multiannual objectives. Schedule of changes in the impairment losses for loans and advances to customers Disclosure Of Changes In The Balance Of Impairment Loss And Allowance For Loans And Advances To Customers [Table Text Block] Disclosure of changes in balance of impairment loss allowance for loans and advances to customers. SMEs and individual entrepreneurs Corporate Loans To SMEs And Individual Entrepreneurs [Member] This member stands for corporate loans made to SMEs and individual entrepreneurs. Recognition of income and expenses Description Of Accounting Policy For Income And Expense, Policy [Policy Text Block] The description of the entity's accounting policy for income and expenses. Internal credit grades [domain] Internal credit grades [domain] Maximum number of beneficiaries Deferred Variable Remuneration, Maximum Number Of Beneficiaries Deferred Variable Remuneration, Maximum Number Of Beneficiaries 2022 variable remuneration Share Based Variable Remuneration Award 2022 [Member] Share Based Variable Remuneration Award 2022 Depreciation and amortisation cost Depreciation and amortisation expense Benefits paid Benefits paid Decrease (increase) in net defined benefit liability (asset) resulting from payments from plan Ramiro Mato Ramiro Mato Ramiro Mato Garca Ansorena [Member] The member that represents an individual key personnel named Ramiro Mato Garca Ansorena. Excess IRB provision on PE Institutional Review Board, General Funds And Surplus Loans Loss Provision The amount of general fund and surplus loans loss provision as specified by institutional review board. External credit grades [domain] External credit grades [domain] Monetizable Monetizable Tax Assets [Member] This member stands for deferred tax assets that may be considered regulatory capital. Categories of financial assets [domain] Categories of financial assets [domain] Dividend income Disclosure of dividends [text block] Individual plaintiff, CEO functions Individual Plaintiff, CEO Functions [Member] Individual Plaintiff, CEO Functions Net additions (disposals) Additions (Disposals) Of Financial Assets At Fair Value Through Other Comprehensive Income, Net The net increase (decrease) in available-for-sale financial assets resulting from additions and (disposals) of those assets. Provision For Compensation And Associated Cost In Respect Of PPI Policies, Interest Provision For Compensation And Associated Cost In Respect Of PPI Policies, Interest [Member] Provision For Compensation And Associated Cost In Respect Of PPI Policies, Interest Basis of consolidation Basis of Consolidation, Policy [Policy Text Block] Disclosure of accounting policy regarding basis of consolidation. Sensitivity of consolidated profit and consolidated equity Foreign Currency Risks [Abstract] No definition available. Exchange differences and other movements Exchange Differences And Other Movements The increase (decrease) in the fair value measurement of liabilities resulting from exchange differences and other movements. Santander Towarzystwo Funduszy Inwestycyjnych S.A. Santander Towarzystwo Funduszy Inwestycyjnych S.A. [Member] Santander Towarzystwo Funduszy Inwestycyjnych S.A. Schedule of exchange differences, net Disclosure Of Exchange Differences, Net [Table Text Block] Tabular disclosure of exchange differences, net. Basis of presentation of the consolidated financial statements Description Of Accounting Policy For Basis Of Presentation [Policy Text Block] Description Of Accounting Policy For Basis Of Presentation Net defined benefit liability (asset) at beginning of period Net defined benefit liability (asset) at end of period Fair value of plan assets at beginning of year Fair value of plan assets at end of year Net defined benefit liability (asset) Financial instruments not credit-impaired Financial instruments not credit-impaired [member] Legal case related to withholding income tax on payments derived from technology services Legal Case Related To Withholding Income Tax On Payments Derived From Technology Services [Member] Legal Case Related To Withholding Income Tax On Payments Derived From Technology Services Fortune Auto Finance Co., Ltd Fortune Auto Finance Co., Ltd [Member] Fortune Auto Finance Co., Ltd Disposal of equity instruments Cancellation of treasury shares Provisions - Provisions for pensions Provisions - Provisions for pensions Surplus (deficit) in plan Commitments and financial guarantees Other Fee And Commission Income, Financial Guarantees The amount of other fee and commission income from financial guarantees. Sensitivity Analysis Variable [Domain] Sensitivity Analysis Variable [Domain] This member stands for aggregate of different variable assumptions used for sensitivity analysis. Purchase of equity instruments Purchase of treasury shares Carrying amount - liabilities Hedging instrument, liabilities Percentage of voting equity interests acquired Percentage of voting equity interests acquired Public Institutions Payables on social security and taxes other than income tax BNP Paribas BNP Paribas [Member] This member represents BNP Paribas. Gains or losses resulting from the accounting for hedges of equity instruments measured at fair value through other comprehensive income, net Other comprehensive income, before tax, gains (losses) on hedging instruments that hedge investments in equity instruments Payment of tax expense other than income tax expense Payment Of Tax Expense Other Than Income Tax Expense Payment Of Tax Expense Other Than Income Tax Expense Pre-retirement cost Pre Retirement Cost Defined Benefit Liability Asset The increase (decrease) in the net defined benefit liability (asset) resulting from pre-retirement cost. Schedule of loans and advances to banks and credit institutions Disclosure Of Detailed Information About Loans And Advances To Banks [Table Text Block] Disclosure Of Detailed Information About Loans And Advances To Banks Pluxee Beneficios Brasil, S.A. Pluxee Beneficios Brasil, S.A. [Member] Pluxee Beneficios Brasil, S.A. Provisions For Employee Benefits And Others [Axis] Provisions For Employee Benefits And Others [Axis] The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table. Schedule of changes in subordinated liabilities Schedule Of Reconciliation Of Subordinated Liabilities [Table Text Block] Tabular disclosure of the changes in subordinated liabilities. Tax losses, deferred tax assets not recognized Tax Losses, Deferred Tax Assets Not Recognized Tax Losses, Deferred Tax Assets Not Recognized Others Eligible Capital Deductions, Other The amount of other adjustments to equity required for computation of Common Equity Tier I (CET I) equity. Furniture and vehicles Furniture And Vehicles [Member] This member stands for a class of property, plant and equipment representing furniture and vehicles Equity component of the compound financial instrument Compound Financial Instrument, Equity Component Compound Financial Instrument, Equity Component Financial assets and liabilities Financial Assets And Liabilities, Category [Member] This member stands for those financial assets and liabilities that comprise the Categories designations in the ifrs taxonomy. Number of geographies with global trade services platform Deferred Variable Remuneration, Milestone, Number Of Geographies With Global Trade Services Platform Deferred Variable Remuneration, Milestone, Number Of Geographies With Global Trade Services Platform Zurich Santander Insurance America, S.L. - Consolidated Zurich Santander Insurance America SL [Member] This member stands for Zurich Santander Insurance America S.L. Mexico MEXICO Non-executive Vice Chair Non Executive Vice Chairman [Member] This member stands for the person serving as the non-executive deputy chairman of the board of directors. Type Of Agreement [Axis] Type Of Agreement [Axis] Type Of Agreement Sensitivity analysis, discount rate adjustment, increase (in basis points) Sensitivity Analysis, Discount Rate Adjustment, Increase Sensitivity Analysis, Discount Rate Adjustment, Increase Derivatives Derivatives [member] Assets Assets, Related Party Transactions The amount of assets attributable to related party transactions. Legal case to request court judgment on the validity of the swaps Legal Case To Request Court Judgment On Validity Of Swaps [Member] This member stands for a legal case to request a court judgment on the validity of the swaps in the jurisdiction of the United Kingdom to which the swaps are subject. Dilutive effect of changes in profit for the period arising from potential conversion of ordinary shares Dilutive Effect Of Potential Conversion Of Ordinary Shares Dilutive Effect Of Potential Conversion Of Ordinary Shares Condensed balance sheets Condensed Balance Sheet [Table Text Block] Discontinued operations, consolidated income and cash flow statements Discontinued Operations, Consolidated Income And Cash Flow Statements [Table Text Block] Discontinued Operations, Consolidated Income And Cash Flow Statements Increase (decrease) annual emoluments, per director (in percentage) Increase (Decrease) Key Management Personnel Compensation, Director Compensation, Per Director, Percentage Increase (Decrease) Key Management Personnel Compensation, Director Compensation, Per Director, Percentage Decrease in cost of credit Percentage Of Decrease In Cost Of Credit The percentage of decrease in cost of credit. Major business combination [member] Major business combination [member] USA electric vehicle leasing incentives Tax Effect Of USA Electric Vehicle Leasing Incentives Tax Effect Of USA Electric Vehicle Leasing Incentives Post-employment plans Post Employment Plans [Member] This member stands for post-employment plans. Number of consecutive stages Foreign Currency Translations, Number Of Stages Represents number of consecutive stages in which foreign currency balances are translated to functional currency. Assets, collateral received and own debt securities issued other than covered bonds and ABSs encumbered Assets Pledged As Collateral For Liabilities Or Contingent Liabilities, Assets, Carrying Value The carrying value of assets that the entity has pledged as collateral for liabilities or contingent liabilities. Credit cards receivables Credit Cards Receivables [Member] This member stands for credit cards receivables. PROFIT OR LOSS ATTRIBUTABLE TO SHAREHOLDERS OF THE PARENT Attributable profit Profit (Loss) Attributable To Shareholders Of Parent The amount of shareholders' equity attributable to profit (loss) for the current period. Other term loans Other Term Loans Receivables [Member] This member stands for other term loans receivable. Number of capital buffer Number Of Capital Buffer Number Of Capital Buffer Classes of share capital [axis] Classes of share capital [axis] Disclosure of fair value measurement of liabilities [table] Disclosure of fair value measurement of liabilities [table] Collateral [Axis] Collateral1 [Axis] Information by category of collateral or no collateral. Subordinated issue, first call date Subordinated Issue, First Call Date Subordinated Issue, First Call Date Other Other Increase (Decrease) In Fair Value Measurement, Liabilities The increase (decrease) in the fair value measurement of liabilities that the entity does not separately disclose in the same statement or note. Percentage of public notary expenses and agency expenses to be paid Percentage Of Public Notary Expenses And Agency Expenses To Be Paid Percentage Of Public Notary Expenses And Agency Expenses To Be Paid Legal proceedings provision, probable loss fully provisioned Legal Proceedings Provision, Probable Loss, Fully Provisioned Legal Proceedings Provision, Probable Loss, Fully Provisioned Asset Swap Model Valuation Technique Asset Swap Model Valuation Technique [Member] Asset Swap Model Valuation Technique TOTAL EQUITY Equity at beginning of period Equity at end of period Equity Equity FINANCIAL ASSETS DESIGNATED AT FAIR VALUE THROUGH PROFIT OR LOSS Financial assets designated at fair value through profit or loss Other financial assets at fair value through profit or loss Financial assets at fair value through profit or loss, designated upon initial recognition or subsequently Schedule of defined benefit obligation expenses recognized in the consolidated income statements Disclosure Of Defined Benefit Obligation Expenses Recognized In Income Statements [Table Text Block] Disclosure of defined benefit obligation expenses recognized in the consolidated income statements. A) Cash flows from operating activities Cash flows from (used in) operating activities, discontinued operations Percent at risk Percentage Of Total Portfolio At Risk The percentage of the total portfolio that is at risk. Total income Gross profit Gross profit Fair value of collateral received or own debt securities issued available for encumbrance Fair Value Of Collateral Received Or Own Debt Securities Issued, Available For Encumbrance Fair Value Of Collateral Received Or Own Debt Securities Issued, Available For Encumbrance Percentage of share capital Shares Sold, Percentage of Share Capital Shares Sold, Percentage of Share Capital Credit Quality [Domain] Credit Quality [Domain] Detail of credit quality ratings calculated for Group management purposes. Issuance by Banco Santander Brasil in November 2021 Issuance By Banco Santander Brasil In November 2021 [Member] Issuance By Banco Santander Brasil In November 2021 Hedging instruments (items not designated) Other Comprehensive Income, Before Tax, Hedging Instruments Not Designated Other Comprehensive Income, Before Tax, Hedging Instruments Not Designated Exchanges differences Exchange differences Other comprehensive income, before tax, exchange differences on translation of foreign operations Expected impact on credit risk provision Impact On Credit Risk Provision Impact On Credit Risk Provision Credit institutions Financial liabilities: credit institutions Deposits Credit Institutions [Member] This member represents deposits of any nature, including credit received and money market operations in the name of credit institutions. Schedule of other financial liabilities Disclosure Of Other Financial Liabilities [Table Text Block] Tabular disclosure of other financial liabilities. Schedule of movement of gross exposure by impairment stage Disclosure Of Movement In Gross Exposure By Impairment Stage [Table Text Block] The tabular disclosure of movement in gross exposure by impairment stage. Schedule of distribution of the Bank's net profit Schedule Of Distribution Of Net Profit [Table Text Block] Schedule Of Distribution Of Net Profit Level 2 Level 2 of fair value hierarchy [member] Deferred multiyear objectives variable remuneration plan first cycle Deferred Multiyear Objectives Variable Remuneration Plan First Cycle 2016 [Member] Information pertaining to the Deferred Multiyear Objectives Variable Remuneration Plan, first cycle (2016). Deferred conditional variable remuneration plan seventh, eighth, ninth, tenth and eleventh cycles Deferred Conditional Variable Remuneration Plan Seventh, Eighth, Ninth, Tenth And Eleventh Cycles 2017, 2018, 2019, 2020 And 2021 [Member] Deferred Conditional Variable Remuneration Plan Seventh, Eighth, Ninth, Tenth And Eleventh Cycles 2017, 2018, 2019, 2020 And 2021 Pension funds Pension Funds [Member] This member stands for pension funds. Schedule of exposure and impairment losses by stage Disclosure Of Credit Quality [Table Text Block] The tabular disclosure of credit quality. Weighted average exercise price of share options outstanding in share-based payment arrangement Weighted average exercise price of share options outstanding in share-based payment arrangement Maximum percentage of appraisal company's total billings to Group Maximum Billings Percentage Maximum percentage of appraisal company's total billings that may be attributable to entity under entity's corporate policy related to independence in twelve month period. Profit/(loss) attributable to the parent Profit (loss) attributable to the Parent Underlying profit attributable to the parent Profit (loss), attributable to owners of parent Sharesave plan Sharesave Plan [Member] Information pertaining to the Sharesave plans. Redemption of treasury shares, par value Redemption Of Treasury Shares, Par Value Redemption Of Treasury Shares, Par Value Non-controlling interest, other elements Non Controlling Interests, Other Elements [Member] This member stands for equity in a subsidiary not attributable, directly or indirectly, to the parent excluding the amount of accumulated items of income and expense (including reclassification adjustments) that are not recognised in profit or loss. Provisions for pre-retirements Provisions For Pre-Retirements Provisions for pre-retirements. Other companies Aggregated individually immaterial joint ventures [member] Advertising Sales and marketing expense Active loans, under IAS 37 Active Loans, Under IAS 37 [Member] Active Loans, Under IAS 37 Gains Gains on disposals of non-current assets Advances to customers Advances To Customers Advances to customers. Type Of Agreement [Domain] Type Of Agreement [Domain] Type Of Agreement [Domain] Major customers [axis] Major customers [axis] IFRS Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Disclosure Of IFRS Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Liabilities secured by mortgage-backed bonds Liabilities Secured By Mortgage-Backed Bonds The amount of liabilities secured by non-asset-backed securities that are, specifically, mortgage-backed bonds held by the entity. Discretionary pension contribution percentage Discretionary Pension Benefit Component, Percentage Discretionary percentage of total award that could be included in contributions to the pension system. Without collateral Without mortgage collateral Non-encumbered assets IFRS Uncollateralized [Member] Information pertaining to instruments that contain no pledge of specific property to serve as protection or security against default. 1 % appreciation of euro, effect on consolidated equity Decrease In Consolidated Equity Due To Reasonably Possible Appreciation Of Entity's Functional Currency The estimated decrease in consolidated equity that would have been caused by an appreciation of entity's functional currency that was reasonably possible at the end of the reporting period. Cost of services provided Defined Benefit Plans, Cost Of Services Provided Defined Benefit Plans, Cost Of Services Provided Cash flow hedges Cash flow hedges [member] Increase (decrease) through business combinations, minority interest Increase (Decrease) Through Business Combinations, Minority Interest Increase (Decrease) Through Business Combinations, Minority Interest Deferred conditional variable remuneration plan and linked to objectives (2023) Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2023 [Member] Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2023 BBB IFRS Standard Poors BBB Rating [Member] BBB credit rating as defined by the external credit rating agency, Standard & Poor's. Banco Santander, S.A., November 2023 Issuance By Banco Santander S.A. In November 2023, First Series [Member] Issuance By Banco Santander S.A. In November 2023, First Series Transfers into Level 3 of fair value hierarchy, assets Transfers into Level 3 of fair value hierarchy, assets Inventories Current inventories Deferred tax assets Deferred tax assets at beginning of period Deferred tax assets at end of period Deferred tax assets Non-Controlling interest Non-controlling interests [member] Attributable to non-controlling interests Comprehensive income, attributable to non-controlling interests Council of the EU blacklist Council Of The EU Blacklist [Member] Council Of The EU Blacklist Accrued dividend Regulatory Capital Adjustment, Accrued Dividend Amount of accrued dividend that is excluded from regulatory capital. Santander Consumer Bank AS Santander Consumer Bank AS [Member] Santander Consumer Bank AS Depreciation rate, property, plant and equipment Depreciation rate, property, plant and equipment Losses Losses on disposals of non-current assets Schedule of detail of other general administrative expenses Disclosure Of Other General And Administrative Expense [Table Text Block] The tabular disclosure of other general and administrative expenses. Customer deposits Deposits Customers, Excluding Poland Disposal [Member] Deposits Customers, Excluding Poland Disposal Equity-instrument-based employee remuneration Description of accounting policy for share-based payment transactions [text block] Residential Residential Residential Loans [Member] This member stands for residential loans receivables. Renegotiation and contractual modifications Renegotiation And Contractual Modifications [Member] Renegotiation And Contractual Modifications Technical guarantees Other Granted Guarantees [Member] Other granted guarantees. Schedule of deposits from central banks and credit institutions Schedule Of Deposits From Central Banks And Credit Institutions [Table Text block] The detail, by classification, counterparty, type and currency, of Deposits from central banks and Deposits from credit institutions in the consolidated balance sheets. Other derivatives Other Derivatives [Member] This member stands for derivative financial instruments that the entity does not separately disclose in the same statement or note. Loans and advances, central banks and credit institutions Interest Income On Loans And Advances To Banks And Credit Institutions Interest Income On Loans And Advances To Banks And Credit Institutions NZD New Zealand, Dollars Write-offs Write-off of impaired balances against recorded impairment allowance Written-off assets Decrease through derecognition, financial assets Financial actuarial (gains)/losses Decrease (increase) in accumulated actuarial losses/profits Decrease (increase) in net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in financial assumptions From transfers Foreign Exchange Gain (Loss), Transfers Foreign Exchange Gain (Loss), Transfers Financial instruments Measurement of financial assets and liabilities and recognition of fair value changes Disclosure of detailed information about financial instruments [line items] Summary of changes in investments Disclosure Of Changes In A Specific Investment, Accounted For Using Equity Method [Table Text Block] Tabular Disclosure Of Changes in a Specific Investment, Accounted For Using Equity Method. Buildings for own use Buildings [member] Inflation rate assumption Actuarial assumption of expected rates of inflation [member] Aggregate amounts for entities accounted for using the equity method Aggregate Amounts For Entities Accounted For Using Equity Method [Member] Aggregated information pertaining to entities accounted for using the equity method. RSU granted (in shares) Number of other equity instruments granted in share-based payment arrangement Net inclusion, fair value measurement, liabilities Inclusion Of Group Entities, Fair Value Measurement, Liabilities Inclusion Of Group Entities, Fair Value Measurement, Liabilities Deferred multiyear objectives variable remuneration plan fourth cycle Deferred Multiyear Objectives Variable Remuneration Plan Fourth, Fifth And Sixth Cycle [Member] Deferred Multiyear Objectives Variable Remuneration Plan Fourth, Fifth And Sixth Cycle Coming from non-banking financial products Portfolio and other management fee income Legal Entity [Axis] Legal Entity [Axis] Liabilities secured by territorial covered bond Liabilities Secured By Covered Bond The amount of liabilities secured by territorial covered bond held by the entity. Local volatility Local Volatility Option Technique [Member] Local Volatility Option Technique Commercial credit Commercial Credit [Member] This member stands for commercial credit receivables. Belén Romana Belén Romana Belen Romana Garcia [Member] The member that represents an individual key personnel named Belen Romana Garcia. Customers excluding the public sector Private Sector [Member] This member represents customers defined as private sector. Excludes public sector customers. Profit (loss) attributable to ordinary equity holders of parent Profit (loss), attributable to ordinary equity holders of parent entity, used in calculating basic earnings per share JPY Japan, Yen Discount rate actuarial assumptions Actuarial assumption of discount rates [member] Schedule of details of hedged exposure/hedged items Disclosure of detailed information about hedged items [text block] Disclosure of financial liabilities [table] Disclosure of financial liabilities [table] Banco Santander, S.A., August 2024 Issuance By Banco Santander S.A. In August 2024 [Member] Issuance By Banco Santander S.A. In August 2024 Santander Bank, National Association Santander Bank National Association [Member] Represents information pertaining to Santander Bank, National Association, a subsidiary of the entity. Demographic actuarial (gains)/losses Demographic actuarial (gains)/losses Decrease (increase) in net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in demographic assumptions Guarantees received committed Collateral sold or repledged in absence of default by owner of collateral, at fair value Disclosure of financial assets that are either past due or impaired [table] Disclosure of financial assets that are either past due or impaired [table] BPA growth objective, result Variable Remuneration, Deferred Payment, BPA Growth, Result Variable Remuneration, Deferred Payment, BPA Growth, Result Geographical areas [axis] Geographical areas [axis] Santander Consumo 7, F.T. Santander Consumo 7, F.T. [Member] Santander Consumo 7, F.T. Business combination, minimum acceptance percentage by Shareholders of acquiree Business Combination, Minimum Acceptance Percentage By Shareholders Of Acquiree Business Combination, Minimum Acceptance Percentage By Shareholders Of Acquiree Non-bank subsidiaries Non Bank Subsidiaries [Member] Information pertaining to subsidiaries of the parent which are not banks. Portion of consideration paid (received) in shares per share Consideration Paid (Received), In Shares Per Share Consideration Paid (Received), In Shares Per Share Revaluation gains (losses) Gains (Losses) On Remeasuring Hedging Instruments Not Designated, Before Tax Gains (Losses) On Remeasuring Hedging Instruments Not Designated, Before Tax Contributions/(surrenders) Contributions Decrease (increase) in net defined benefit liability (asset) resulting from contributions to plan Number of customers acquired in Pago Nxt (in percentage) Deferred Variable Remuneration, Milestone, Pago Nxt, Number Of Customers Acquired, Percentage Deferred Variable Remuneration, Milestone, Pago Nxt, Number Of Customers Acquired, Percentage Goodwill and intangible assets Intangible Assets And Goodwill, Net Of Residual Value The amount of intangible assets and goodwill, net of residual value, held by the entity. Redemptions and repurchases Subordinated Liabilities, Net Redemptions And Repurchases Subordinated Liabilities, Net Redemptions And Repurchases Other financial assets Other cash and cash equivalents Number of unfavorably cases ruled by federal supreme court Number Of Unfavorably Cases Ruled By Federal Supreme Court Number Of Unfavorably Cases Ruled By Federal Supreme Court Time deposits Time Deposits [Member] Information pertaining to time deposits. Other intangible assets Intangible assets Intangible assets, beginning balance Intangible assets, end balance Intangible assets other than goodwill Period for approval of the sharesave scheme by UK tax authorities Period Of Approval Sharesave Scheme The period for approval of the Sharesave Scheme by UK tax authorities. Of which, credit institutions deposit guarantee fund and single resolution fund Deposit Guarantee Fund Miscellaneous Other Operating Expense The amount of deposit guarantee fund operating expense that the entity does not separately disclose in the same statement or note. Other fixed-income securities Other Fixed Income Debt Securities [Member] This member stands for other fixed income debt securities. Property, plant and equipment by operating lease status [axis] Property, plant and equipment by operating lease status [axis] Segments [domain] Segments [domain] CASH, CASH BALANCES AT CENTRAL BANKS AND OTHER DEPOSITS ON DEMAND TOTAL CASH AND CASH EQUIVALENTS AT END OF THE YEAR (EXCLUDING ENTITIES ON SOLD) Cash, cash balances at central banks and other deposits on demand Cash, cash balances at central banks and other deposits on demand CASH AND CASH EQUIVALENTS AT BEGINNING OF THE YEAR CASH AND CASH EQUIVALENTS AT END OF THE YEAR Cash and cash equivalents Deposits Deposit [Member] Deposit SC Austria S.à r.l., Compartment Consumer 2025-1 SC Germany S.A., Compartment Consumer 2025-1 [Member] SC Germany S.A., Compartment Consumer 2025-1 Disposals Decrease Through Disposals, Financial Assets The decrease in financial assets resulting from disposals. Mortgage-backed Bonds, outstanding face value Mortgage-Backed Bonds, Outstanding, Face Value Mortgage-Backed Bonds, Outstanding, Face Value Variable remuneration (bonus) - Immediate payment Long Term Incentive Plan [Member] Information pertaining to the Long-term incentive (Performance Share Plan or "ILP"). Pensionable base, expressed as a percent of fixed remuneration Defined Benefit Obligation, Pensionable Base, Death Or Disability Percentage The percentage of fixed remuneration paid out in the event of death or disability of plan participants. Revaluation reserves Revaluation surplus [member] Schedule of technical reports includes the fees paid by various Group companies Disclosure Of Technical Reports And Other [Table Text Block] The tabular disclosure of technical reports includes the fees paid by the various Group companies. Number of shares owned by third parties managed by Group management companies (in shares) Number Of Shares Owned By Third Parties Managed By Group Management Companies The number of shares owned by third parties and managed by Group management companies or jointly managed. To stage 1 from stage 3 Increase (Decrease) Through Transfers From Stage 3 To Stage 1 Financial Assets The increase (decrease) in financial assets resulting from transfers from credit risk stage 3 to stage 1. Gain or losses from hedge accounting, net Gains Or Losses From Hedge Accounting Net Net amount of gains or losses from hedge accounting recognized in profit or loss. (Charge)/Credit to income Deferred Tax Expense (Credit) Recognised In Profit Or Loss The amount of tax income or expense relating to changes in deferred tax liabilities, recognised in profit or loss. Shares owned by third parties managed by Group management companies, percentage of share capital Shares Owned By Third Parties Managed By Group Management Companies, As Percentage Of Total Share Capital The percentage of shares owned by third parties and managed by Group management companies or jointly managed in relation to total share capital. Amortization and impairment Amortisation And Impairment, Intangible Assets Other Than Goodwill The amount of amortisation or impairment of intangible assets other than goodwill. Sensitivity analysis, perpetuity growth rate adjustment, increase (in basis points) Sensitivity Analysis, Perpetuity Growth Rate Adjustment, Increase Sensitivity Analysis, Perpetuity Growth Rate Adjustment, Increase Other changes in equity Increase (Decrease) In Equity Other Than Comprehensive Income The amount of change in equity resulting from transactions and other events other than those classified as comprehensive income. Other Increase (Decrease) In Non-Controlling Interest, Excluding Other Comprehensive Income The increase in noncontrolling interest resulting from changes other than other comprehensive income. Business combinations [axis] Business combinations [axis] Trading derivatives Trading Derivatives [Member] Trading Derivatives Investments Investment [Abstract] Disclosure Of Significant Investments In Associates and Joint Ventures [Abstract] Pessimistic scenario 2 Pessimistic Scenario Two [Member] Represents information pertaining to pessimistic scenario two. PROVISIONS Provisions Provisions Balances at beginning of year Balances at end of year Provisions Land and buildings Land and buildings [member] Other commitments granted Other Commitments [Member] Information pertaining to commitments other than loan commitments and financial guarantees. Commission expense Commission Expense, Related Party Transactions The amount of commission expense attributable to related party transactions. Dividend [Axis] Dividend [Axis] Dividend Agreement For The Sale Of Santander Bank Polska S.A. Agreement For The Sale Of Santander Bank Polska S.A. [Member] Agreement For The Sale Of Santander Bank Polska S.A. Changes in financial instruments, Assets Reconciliation of changes in fair value measurement, assets [abstract] Hedges of net investments in foreign operations (Effective portion) Reserve of gains and losses on hedging instruments that hedge investments in equity instruments Interest paid in remuneration of issuances Subordinated Liabilities, Interest Paid In Remuneration Of Issuances Subordinated Liabilities, Interest Paid In Remuneration Of Issuances Product and Service [Domain] Product and Service [Domain] Profit Distribution [Table] Schedule Of Profit Distribution [Table] Profit Distribution [Table] Santander UK PLC and Santander UK Group Holdings Santander UK PLC And Santander UK Group Holdings [Member] Santander UK PLC And Santander UK Group Holdings Schedule of marketable securities Schedule Of Marketable Debt Securities [Table Text block] The detail, by classification and type, of Marketable debt securities . Percentage secured by mortgage Loans, Percentage Secured By Mortgage Percentage of loans secured by mortgage. Financial liabilities at fair value with changes in results attributable to changes in credit risk Income tax relating to changes in fair value of financial liability attributable to change in credit risk of liability included in other comprehensive income Disclosure of attribution of expenses by nature to their function [table] Disclosure of attribution of expenses by nature to their function [table] Disclosure Of Other Equity Instruments And Own Shares [Line Items] Disclosure Of Other Equity Instruments And Own Shares [Line Items] Disclosure Of Other Equity Instruments And Own Shares Rate for which company is considered significant (in percentage) Rate For Which Group Holding In A Company Is Considered Significant, Percent Rate For Which Group Holding In A Company Is Considered Significant, Percent Annual interest rate Subordinated Liabilities, Interest Rate Annual interest rate of the subordinated liabilities. Disclosure of maturity analysis of debt instruments, book value and notional amounts Disclosure of maturity analysis for non-derivative financial liabilities Disclosure of maturity analysis for non-derivative financial liabilities [text block] Cumulative annual CPI growth Actuarial assumption of expected rates of inflation For own-use Property, plant and equipment not subject to operating leases [member] Options cancelled (net) or not exercised (in shares) Number of share options expired in share-based payment arrangement Other comprehensive income Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss [abstract] Number of other components Number Of Associates, Joint Ventures Or Listed Companies Of Which The Entity Holds More Than Five Percent Interest The number of associates, joint ventures or list companies of which the entity owns more than 5% interest. Schedule of details of hedging instruments Disclosure of detailed information about hedging instruments [text block] Interest rate risk Interest rate Interest rate risk [member] Percentage of anti cyclical buffer on common equity Tier1 capital Common Equity Tier One Capital Countercyclical Buffer Percentage Percentage of countercyclical buffer on common equity Tier1 capital. Dividend income Dividend income Santander Portugal Santander Portugal [Member] Information pertaining to Santander Portugal. Unrecognised net assets for pensions Unrecognized Net Assets For Pensions Unrecognized net assets for pensions. Chair of the innovation and technology committee The Innovation And Technology Committee, Chairman [Member] The Innovation And Technology Committee, Chairman Schedule summarising remuneration related to welfare system Disclosure Of Transactions Between Related Parties, Remuneration, Welfare System [Table Text Block] Tabular disclosure of remuneration by director between the entity and its related parties related to specified welfare system. Subordinated Liabilities, Preference Shares, Second Series Subordinated Liabilities, Preference Shares, Second Series [Member] Subordinated Liabilities, Preference Shares, Second Series Developed consolidated land Developed Land Collateral [Member] This member stands for collateral in the form of developed land. Percentage of the registry expenses to be paid Percentage Of The Registry Expenses To Be Paid Percentage Of The Registry Expenses To Be Paid Non-current assets held for sale Non-Current Assets Held-For-Sale That Will Not Be Reclassified To Profit Or Loss, Before Tax Non-Current Assets Held-For-Sale That Will Not Be Reclassified To Profit Or Loss, Before Tax More than 5 years Later than 5 years More than five years Later than five years [member] Inflation swap Inflation Swap Contract [Member] Inflation Swap Contract Payments Investments (-) Outflows of cash from investing activities Classes of financial assets [domain] Classes of financial assets [domain] Clearing houses Items in course of transmission to other banks Members of the innovation and technology committee Innovation and technology committee Innovation And Technology Committee [Member] Innovation And Technology Committee Intangible assets - Other intangible assets Disclosure of intangible assets [text block] Spanish supreme court, mortgage expenses Spanish Supreme Court, Mortgage Expenses [Member] Spanish Supreme Court, Mortgage Expenses Interest rate swaps Interest rate swap contract [member] Price Price, Measurement Input [Member] Price, Measurement Input Benefits paid due to settlements Decrease Though Payments In Respect Of Settlements, Provision Decrease Though Payments In Respect Of Settlements, Provision Lease Liabilities Interest expense on lease liabilities Use of accounting estimates Disclosure of accounting judgements and estimates [text block] Less than or equal to 40% LTB Less Than Or Equal To 40 Percent [Member] Loan-to-value (LTV) ratio less than or equal to 40%. Unpaid capital which has been called up Unpaid Capital Called Up Unpaid Capital Called Up Deferred payment, long term, number of deferrals Variable Remuneration, Deferred Payment, Long Term, Number Of Deferrals Variable Remuneration, Deferred Payment, Long Term, Number Of Deferrals 5-Year UST Rate (US Dollar) UST Rate Five Year US Dollar [Member] UST Rate Five Year US Dollar Manheim growth Estimation Of Expected Losses, Manheim Growth Rate Estimation Of Expected Losses, Manheim Growth Rate Segment consolidation items [domain] Segment consolidation items [domain] Senior managers, country heads, other executives and identified staff with total variable remuneration specified amount Division Managers Country Heads Other Executives And Identified Staff With Total Variable Remuneration Specified Amount [Member] Represents division managers, country heads of countries that represent at least 1% of the Group's economic capital, other executives of the Group with a similar profile and members of the Identified Staff with specified total variable remuneration. Deferred conditional variable remuneration plan and linked to objectives (2022) Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2022 [Member] Deferred Conditional Variable Remuneration Plan And Linked To Objectives 2022 Digital Transformation Award 2023 Digital Transformation Award 2023 [Member] Digital Transformation Award 2023 Non- loans advances Non Loan Advances [Member] Information pertaining to non-loan advances. Gains/(losses) on settlements Gains (Losses) On Liquidation, Net Defined Benefit Liability (Asset) Gains (Losses) On Liquidation, Net Defined Benefit Liability (Asset) Santander Consumer Bank S.p.A. Santander Consumer Bank S.p.A. [Member] Santander Consumer Bank S.p.A. Basis Risk Basis Risk [Member] Basis Risk Number of subsidiaries Number Of Subsidiaries The number of subsidiaries. Redemption of treasury shares, shares Redemption Of Treasury Shares, Shares Redemption Of Treasury Shares, Shares Issuance by Banco Santander S.A. in August 2023 Issuance By Banco Santander S.A. In August 2023 [Member] Issuance By Banco Santander S.A. In August 2023 Hyundai Capital Bank Europe GmbH Italy Hyundai Capital Bank Europe GmbH Italy [Member] Hyundai Capital Bank Europe GmbH Italy Goodwill Goodwill [member] Other equity instruments Other equity interest [member] Fair value of financial instruments [Abstract] Fair Value of Financial Instruments [Abstract] Fair value of financial instruments [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES Cash flows from (used in) operating activities Share-based payment arrangement Disclosure of terms and conditions of share-based payment arrangement [line items] Schedule of other liabilities Schedule Of Other Liabilities [Table Text Block] Tabular information related to other liabilities. Investments Disclosure of interests in other entities [text block] Non-current assets held for sale Other Reserves, Non-Current Assets Held For Sale Not Reclassified To Profit Or Loss Other Reserves, Non-Current Assets Held For Sale Not Reclassified To Profit Or Loss Incorporation of Group companies, net Insurance Contracts Linked To Pensions, Assets From Incorporation Of Entities, Net Increase in insurance contracts linked to pensions from incorporation of entities. Number of countries with PagoFX global platform Deferred Variable Remuneration, Milestone, Number Of Countries With PagoFX Global Platform Deferred Variable Remuneration, Milestone, Number Of Countries With PagoFX Global Platform Entity [Domain] Entity [Domain] Other operating income Miscellaneous other operating income Insurance contracts [axis] Insurance contracts [axis] Members of the audit committee Audit committee Audit Committee [Member] This member stands for those persons serving as members of the audit committee of the board of directors. Property, fixtures and supplies (note 2.k) Property service charge expense Schedule summarising remuneration related to provisions for retirement pensions and supplementary benefits Disclosure Of Transactions Between Related Parties, Remuneration, Provisions For Retirement Pensions And Supplementary Benefits [Table Text Block] Tabular disclosure of remuneration between the entity and its related parties related to provisions for retirement pensions and supplementary benefits. Document Fiscal Year Focus Document Fiscal Year Focus Retired executive directors Directors Retired [Member] This member stands for retired executive directors. Financial assets at amortized cost Adjustments for decrease (increase) in financial assets measured at amortised cost Openbank Openbank Segment [Member] Openbank, formerly Digital Consumer Bank (Consumer) Deposits on demand Demand Deposit [Member] Infromation pertaining to demand deposits. Change in provision assuming 100bp increase in interest rate (as a percent) Percent Change In Provision Assuming 100 Basis Point Increase In Interest Rate Percent Change In Provision Assuming 100 Basis Point Increase In Interest Rate Non-current assets held for sale Income Tax Relating To Non Current Assets Held For Sale Included In Other Comprehensive Income Income Tax Relating To Non Current Assets Held For Sale Included In Other Comprehensive Income Loans granted Other Fee And Commission Income, Loans Granted Other Fee And Commission Income, Loans Granted Other financial institutions (financial business activity) Other financial institutions and: individual shareholder Other Financial Institutions [Member] This member stands for other financial institutions (Financial business activity) customers. Income tax at tax rate applicable in Spain (30%) Tax Expense (Income) At Applicable Tax Rate, Including Discontinued Operations Tax Expense (Income) At Applicable Tax Rate, Including Discontinued Operations Total North America North America [Member] Classes of Deferred Tax Assets [Axis] Classes Of Deferred Tax Assets [Axis] The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table. Gains (losses) on financial instruments [abstract] Gains (losses) on financial instruments [abstract] Types of interest rates [domain] Types of interest rates [domain] Schedule of other assets Schedule Of Other Assets1 [Table Text Block] Tabular disclosure of the carrying amounts of other assets, including other current assets and other noncurrent assets. Furniture Furniture [Member] This member stands for a class of property, plant and equipment representing furniture. Deposits [Line Items] Schedule Of Deposits [Line Items] Deposits [Line Items] Rest of Europe Rest Of Europe [Member] This member stands for other countries included in the rest of Europe. Excludes Spain, Portugal, Italy, Greece, Ireland, United Kingdom, and Poland. Sensitivity Analysis Variable [Axis] Sensitivity Analysis Variable [Axis] The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table. Discounting Cash Flows On Inflation Swap Rate Flow Discounting Method On Inflation Swap Rate [Member] Flow Discounting Method On Inflation Swap Rate Financial guarantees Description of accounting policy for financial guarantees [text block] Disclosure of high quality liquid assets Disclosure Of High Quality Liquid Assets [Table Text Block] Disclosure Of High Quality Liquid Assets Customer Deposits [Line Items] Schedule Of Customer Deposits [Line Items] Customer Deposits [Line Items] Securitised mortgage bonds Securitized Mortgage Bonds [Member] Securitized Mortgage Bonds. Key management personnel compensation Key management personnel compensation ICO loans, granted as result of the pandemic ICO Loan, Granted As Result Of The Pandemic ICO Loan, Granted As Result Of The Pandemic Percentage of equity interests held by significant shareholders, minimum threshold Percentage Of Equity Interests Held By Significant Shareholders, Minimum Threshold Percentage Of Equity Interests Held By Significant Shareholders, Minimum Threshold Number of geographies with global platform SuperDigital Deferred Variable Remuneration, Milestone, Number Of Geographies With Global Platform SuperDigital Deferred Variable Remuneration, Milestone, Number Of Geographies With Global Platform SuperDigital Foreign government debt securities IFRS Foreign Government Debt Securities [Member] Debt securities issued by a national, local, or municipal government not within the country of domicile of the reporting entity. Disclosure of initial application of standards or interpretations [table] Disclosure of initial application of standards or interpretations [table] Digital Transformation Award 2024 Digital Transformation Award 2024 [Member] Digital Transformation Award 2024 URD/MXN United States Dollar And Mexican Peso [Member] United States Dollar And Mexican Peso On demand On demand [member] Deferred amount in shares not linked to long-term objectives (in shares) Key Management Personnel Compensation, Long Term And Deferred Compensation, Not Linked To Long-Term Objectives Shares Key Management Personnel Compensation, Long Term And Deferred Compensation, Not Linked To Long-Term Objectives Shares Risk adjustment for non-financial risk Risk adjustment for non-financial risk [member] Investments Losses on disposals of investments Disclosure of unconsolidated structured entities [table] Disclosure of unconsolidated structured entities [table] Other operating assets Adjustments for decrease (increase) in other assets Santander US Capital Markets LLC Santander US Capital Markets LLC [Member] Santander US Capital Markets LLC Pension system balance Assets of benefit plan Level 1 Capital IFRS Tier One Leverage Capital Tier 1 Leverage Capital as defined in international regulations. Also called Core Capital. Foreign currency balance translation differences and other items Deferred Tax Expense Tax Asset Income Tax Relating To Components Of Foreign Currency Balance Translation Differences And Other Items The amount of income tax relating to amounts recognized from foreign currency balance translation differences and other items. Santander Consumer Germany Santander Consumer Germany [Member] Represents information pertaining to Santander Consumer Germany, a subsidiary of the entity. Intangible assets Description of accounting policy for intangible assets and goodwill [text block] Profit attributable to shareholders of the parent Profit (Loss) Attributable To Shareholders Of Parent [Member] This member stands for the portion of total equity representing net profit or loss attributable to parent. Disclosure of detailed information about debt instruments explanatory Disclosure Of Detailed Information About Debt Instruments Explanatory [Table Text Block] Disclosure Of Detailed Information About Debt Instruments Explanatory Total South America South America [Member] Secured loans Secured Loans Receivable [Member] This member stands for secured loan receivables. 1 % depreciation of euro, effect on consolidated profit Increase In Consolidated Profit Due To Reasonably Possible Depreciation Of Entity's Functional Currency The estimated increase in consolidated profit that would have been caused by a depreciation of entity's functional currency that was reasonably possible at the end of the reporting period Revaluation gains (losses) Gains (losses) on hedges of net investments in foreign operations, before tax A IFRS Standard Poors A Rating [Member] "A" credit rating as defined by the external credit rating agency, Standard & Poor's. Cash flow hedge/currency translation reserve- Discontinued hedges Cash Flow Reserves Or Conversion Reserves, Discontinued Hedges A component of equity representing the reserve of cash flow hedges and reserve of exchange differences on translation in relation to hedging relationships for which hedge accounting is no longer applied. Financial assets at fair value through other comprehensive income Financial assets measured at fair value through other comprehensive income Households - other Households Other [Member] This member stands for households customers. Auditor Firm [Axis] Auditor Firm [Axis] Auditor Firm Credit institutions Loans and advances: credit institutions Loans And Advances, Credit Institutions [Member] This member represents the credit of any nature, including deposits and money market operations, in the name of credit institutions. Banco Comercial e de Investimento Sudameris S.A Banco Comercial e de Investimento Sudameris S.A [Member] Banco Comercial e de Investimento Sudameris S.A Investment, Name [Axis] Investment, Name [Axis] Vested obligations to retired employees Defined Benefit Obligation To Vested Obligations To Retired Employees At Present Value The present value, without deducting any plan assets, of expected future payments required to settle the vested obligations to retired employees resulting from employee service in the current and prior periods. Mortgage Letters Mortgage Letters, Measurement Input [Member] Mortgage Letters, Measurement Input Impairment losses charged to income Impairment losses charged to profit or loss Impairment loss recognised in profit or loss Tax services Auditor's remuneration for tax services Ownership interest in subsidiary Proportion of ownership interest in subsidiary Disposal of major subsidiary Disposal of major subsidiary [member] Period of suspension of economic plan process Period Of Suspension Of Economic Plan Processes The period of time for which all economic plan processes, such as those that gave rise to Planos Economicos civil suits, are ordered suspended. Change in CVA (as a percent) Financial Instruments, Credit Valuation Adjustment, Increase (Decrease) Increase (decrease) in credit valuation adjustment from prior year as a percent. Entity Registrant Name Entity Registrant Name Basic (in euro per share) Basic earnings (loss) per share (in euro per share) Basic earnings (loss) per share Measurement [axis] Measurement [axis] Loans And Advances To Customers [Table] Loans And Advances To Customers [Table] Disclosure of information about loans and advances to customers. Percentage of annual net profit required to be transferred to the legal reserve Percentage Of Annual Net Profit Required To Be Transferred To Legal Reserve Percentage of annual net profit required to be transferred to the legal reserve under the Consolidated Spanish Limited Liability companies Law. Financial assets offset in the consolidated balance sheets Net financial assets subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position [abstract] Deferred Multiyear Objectives Variable Remuneration Plan Tenth Cycle Deferred Multiyear Objectives Variable Remuneration Plan Tenth Cycle [Member] Deferred Multiyear Objectives Variable Remuneration Plan Tenth Cycle Variable subject to long-term objectives in shares Instrument payment Key Management Personnel Compensation, Variable Share-Based Long-Term Employee Benefits The amount of variable share-based compensation to key management personnel in the form of other long-term employee benefits. Deferred payment percentage Variable Remuneration, Deferred Percentage The percentage of variable remuneration with deferred payment during the period. Deferred conditional variable remuneration plan sixth cycle Deferred Conditional Variable Remuneration Plan Sixth Cycle 2016 [Member] Information pertaining to the Deferred Conditional Variable Remuneration Plan Sixth Cycle (2016). Number of transactions (in loans) Financing Receivables, Modifications, Number Of Contracts Number of financing receivables with modifications of contractual future cash flows. Other liabilities Other Liabilities, Policy [Policy Text Block] Disclosure of accounting policy regarding liabilities classified as other. By collection and return of effects Assigned Third Party Commissions Collection Expense The amount of commissions assigned to third parties from collection and return of effects. Time horizon Time Horizon, Value At Risk And Expected Shortfall Confidence Level, Period Time Horizon, Value At Risk And Expected Shortfall Confidence Level, Period 2025 Program, First 2025 Program, First [Member] 2025 Program, First Non-current assets held for sale and associated liabilities Proceeds from disposal of non-current assets or disposal groups classified as held for sale and discontinued operations Retail & Commercial Banking Retail And Commercial Banking [Member] This member represents retail and commercial banking. Loans and receivables Loans and receivables, category [member] Disclosure of associates [table] Disclosure of associates [table] Transactions in transit Other payables Other currencies Other Currencies [Member] Represents other currencies. Foreclosed assets Decrease Through Foreclosure The decrease in financial assets resulting from foreclosures. Legal proceedings provision, possible loss, contingent liabilities Estimated financial effect of contingent liabilities Banking book Banking Book [Member] This member represents financial assets and liabilities held to maturity. Excludes assets and liabilities held for trading. Present value method Present Value Method [Member] Present Value Method Swap rate Swap Rate, Measurement Input [Member] Swap Rate, Measurement Input Schedule of offsetting of financial instruments Disclosure of offsetting of financial assets and financial liabilities [text block] Assets subject to netting and collateral arrangements on balance sheet Net financial assets subject to offsetting, enforceable master netting arrangements or similar agreements Taxes and other legal contingencies Taxes And Other Legal Contingencies Provision [Member] This member represents the provision for taxes and other legal contingencies. Items that may be reclassified to profit or loss Income Tax Relating To Components Of Other Comprehensive Income That Will Be Reclassified To Profit Or Loss Including Share Of OCI Of Associates And Joint Ventures The amount of income tax relating to amounts recognised in other comprehensive income that will be reclassified to profit or loss, including share of OCI of associates and joint ventures accounted for using the equity method. Developed land Developed Consolidated Land [Member] This member stands for loans for developed consolidated land. Loan losses Loan Losses [Member] This member stands for loan losses. Schedule of insurance contracts linked to pensions Disclosure Of Insurance Contracts Linked To Pensions [Table Text Block] Disclosure of insurance contracts linked to pensions. Central banks Loans And Advances, Central Banks [Member] This member stands for credit of any nature, including deposits and money market operations received from the central bank in the entity's domicile country or other central banks. NON-CONTROLLING INTEREST Non-controlling interests Non-controlling interests Reserve of hedge of net investments in foreign operations and exchange differences on translation Reserve Of Hedge Of Net Investments In Foreign Operations Effective Portion And Exchange Differences On Translation A component of equity representing hedges of net investments in foreign operations, effective portion, and exchange differences on translation of financial statements of foreign operations recognised in other comprehensive income and accumulated in equity. Debt securities Debt instruments Debt securities [member] Revaluation gains (losses) Changes in the fair value of equity instruments measured at fair value through other comprehensive income (EIGR) Gains (losses) on financial assets measured at fair value through other comprehensive income, before tax Segment consolidation items [axis] Segment consolidation items [axis] Staff costs Disclosure of employee benefits [text block] Liabilities secured by mortgage-backed securities Liabilities Secured By Mortgage-Backed Securities The amount of liabilities secured by asset-backed securities that are, specifically, mortgage-backed securities held by the entity. 2024 Program, First 2024 Program, First [Member] 2024 Program, First Financial assets held-for-trading Adjustments for decrease (increase) in financial assets held for trading Disclosure of analysis of other comprehensive income by item [table] Disclosure of analysis of other comprehensive income by item [table] Corporate & Investment Banking Corporate And Investment Banking Segment [Member] Information pertaining to the Corporate and Investment Banking (CIB) (formerly Santander Global Corporate Banking) segment. This business reflects the revenues from global corporate banking, investment banking and markets worldwide including treasuries managed globally (always after the appropriate distribution with Retail Banking customers), as well as equities business. All Currencies [Domain] All Currencies [Domain] 5-Year Mid-Swap Rate (Euro) Mid Swap Rate Five Year Euro [Member] This member stands for the 5-year Euro Mid-Swap Rate. Contract termination, notice period Contract Termination, Notice Period Contract Termination, Notice Period Disclosure of operating segments [abstract] Disclosure of operating segments [abstract] Prepayment rate Constant prepayment rate, measurement input [member] Deferred Multiyear Objectives Variable Remuneration Plan Ninth Cycle Deferred Multiyear Objectives Variable Remuneration Plan Ninth Cycle [Member] Deferred Multiyear Objectives Variable Remuneration Plan Ninth Cycle Schedule of preferred shares and securities by issuer Disclosure Of Preference Shares And Preferred Securities By Issuer [Table text block] Tabular disclosure of preference shares and preferred securities by issuer. TANGIBLE ASSETS Tangible assets Balance, at the beginning of the period Balance, at the end of the period Tangible assets Tangible Assets The amount of tangible assets that are both held for use and expected to used during more than one period. May include property, plant and equipment and investment properties. Bruce Carnegie Brown Bruce Carnegie Brown Bruce Carnegie Brown [Member] The member that represents an individual key personnel named Bruce Carnegie-Brown. Exchange differences and other items Exchange differences and other items Increase (decrease) in net defined benefit liability (asset) resulting from changes in foreign exchange rates, net defined benefit liability (asset) Changes in property loans Increase (decrease) in financial assets [abstract] Expected rate of return on reimbursement rights Insurance Contract Linked To Defined Benefit Plans Expected Rate Of Return On Reimbursement Rights Expected rate of return on reimbursement rights for insurance contract linked to defined benefit plan. Payments Outflows Of Cash From Financing Activities The cash outflow from financing activities. Other general administrative expenses Disclosure of general and administrative expense [text block] Non-controlling interests, excluding profit (loss) for the current period Non-Controlling Interests, Excluding Profit (Loss), Attributable To Non-Controlling Interests The amount of equity in a subsidiary not attributable, directly or indirectly, to a parent excluding the profit (loss) attributable to non-controlling interests for the current period. Former directors of the bank Former Directors Of The Bank [Member] This member represents former directors of the Bank. Condensed Statement of Comprehensive Income [Table] Condensed Statement of Comprehensive Income [Table] Corporate debt Corporate Debt [Member] Corporate Debt Valuation adjustments for impairment Valuation Adjustment For Impairment Financial Instrument Type [Member] Information pertaining to valuation adjustments for impairments as a component of financial instruments. Commitment fees Other Fee And Commission Income, Commitment Fees The amount of other fee and commission income from commitment fees. Credit derivatives sold Sold Credit Derivatives [Member] This member stands for financial guarantees in the form of sold credit derivatives Deferral period Variable Remuneration, Deferral Period The deferral period to pay variable remuneration or bonus. Voluntary reserves Voluntary Reserve A component of equity representing voluntary reserves. Schedule of changes in fair value of plan assets Disclosure of fair value of plan assets [text block] Employee Benefits Classes of employee benefits expense [abstract] Other Other Cost Or Gain Charged To Income Statement Related To Defined Benefits Other costs or gains charged to income statement related to defined benefits. TAX ASSETS Tax assets Tax Assets The excess of amount paid for tax in respect of current, prior, and future periods over the amount due for those periods. Repurchase agreements, value Financial Liabilities At Fair Value Through Profit Or Loss And Financial Liabilities At Fair Value Through Profit Or Loss That Meet The Definition Of Held For Trading, Repurchase Agreement, Amount Financial Liabilities At Fair Value Through Profit Or Loss And Financial Liabilities At Fair Value Through Profit Or Loss That Meet The Definition Of Held For Trading, Repurchase Agreement, Amount Increase in existing provisions Increase in existing provisions, other provisions Number of largest groups Number Of Groups The number of groups. Other gains (losses) and provisions Other gains (losses) and provisions Other Non Financial Gains (Losses) The amount of other non-financial gains (losses). Cash outflow of leases Cash outflow for leases Social Security costs Social security contributions Liabilities secured by asset-backed securities Liabilities Secured By Asset-Backed Securities The amount of liabilities that are secured by asset-backed securities held by the entity. Litigation Case [Axis] Litigation Case [Axis] Matching liabilities, contingent liabilities or securities lent Assets Pledged As Collateral For Liabilities Or Contingent Liabilities, Associated Liabilities, Carrying Value The carrying value of liabilities associated with assets that the entity has pledged as collateral for liabilities or contingent liabilities. Foreign exchange Other Fee And Commission Income, Foreign Exchange The amount of other fee and commission income from foreign exchange transactions. Provision for restructuring Restructuring provision [member] Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [table] Disclosure of reconciliation of changes in loss allowance and explanation of changes in gross carrying amount for financial instruments [table] Members of the responsible banking, sustainability and culture committee Responsible banking, sustainability and culture committee Responsible Banking Sustainability And Culture Committee [Member] Information pertaining to the Responsible Banking Sustainability and Culture Committee. Earning assets Earning Assets [Member] Earning Assets Other Other Miscellaneous Assets Assets classified as Other Assets, not elsewhere specified. Percentage of equity interests held by a single shareholder residing in tax haven, minimum threshold Percentage Of Equity Interests Held By A Single Shareholder Residing In Tax Haven, Minimum Threshold Percentage Of Equity Interests Held By A Single Shareholder Residing In Tax Haven, Minimum Threshold Number of series of convertible preferred stock issued Number Of Series Of Convertible Preferred Stock Issued Number Of Series Of Convertible Preferred Stock Issued Share premium Share premium [member] Maximum number of shares to be delivered (in shares) Maximum Number Of Share Options To Be Delivered In Share-Based Payment Arrangement, Deferred Variable Maximum Number Of Share Options To Be Delivered In Share-Based Payment Arrangement, Deferred Variable Others Defined Benefit Plans, Others Defined Benefit Plans, Others Disclosure of breakdown of equity instruments Disclosure Of Equity Financial Instruments [Table Text Block] The disclosure for equity financial instruments. Disclosure of details of main interest and similar expenses Disclosure Of Interest Expense [Table Text Block] The tabular disclosure of interest expense. Attributable to the parent Comprehensive income, attributable to owners of parent NOK Norway, Krone Forbearance portfolio Forborne Loan Portfolio, Amount The amount of forborne loan portfolio. Central banks Deposits Central Banks [Member] This member represents deposits of any nature, including credit received and money market operations received from the central bank of the domicile country or other central banks. TOTAL LIABILITIES Total liabilities Liabilities AUD Australia, Dollars Associates and joint ventures Associates And Joint Ventures [Member] This member stands for the entities over with the investor has significant influence and for joint ventures in which the entity is a joint venturer. A venturer is a party to a joint venture and has joint control over that joint venture. Variable - immediate payment in cash Variable remuneration in cash Key Management Personnel Compensation, Short-Term Employee Benefits, Variable Cash Compensation The amount of variable cash compensation to key management personnel in the form of short-term employee benefits. TOTAL CASH AND CASH EQUIVALENTS AT END OF PERIOD ASSOCIATED WITH NON-CURRENT ASSETS HELD FOR SALE Cash and cash equivalents classified as part of disposal group held for sale Actuarial assumption of medical cost trend rates Actuarial assumption of medical cost trend rates Issuance by Banco Santander S.A. in March 2024 Issuance By Banco Santander S.A. In March 2024 [Member] Issuance By Banco Santander S.A. In March 2024 Investments Gains on disposals of investments Gains on disposals of investments Other reclassifications Other Reclassification Adjustments On Non-Current Assets Classified As Held For Sale, Before Tax Other Reclassification Adjustments On Non-Current Assets Classified As Held For Sale, Before Tax TSR minimum metric, target Variable Remuneration, Deferred Payment, TSR Minimum Metric, Target Variable Remuneration, Deferred Payment, TSR Minimum Metric, Target Other interest income Interest Income From Other Financial Assets [Member] Interest Income From Other Financial Assets Financial assets at fair value through other comprehensive income Adjustments for decrease (increase) in financial assets measured at fair value through other comprehensive income Changes in the fair value of equity instruments measured at fair value through other comprehensive income (hedging instrument) Other Comprehensive Income, Before Tax, Gains (Losses) On Hedged Instrument Other Comprehensive Income, Before Tax, Gains (Losses) On Hedged Instrument Systematic risk requirement Common Equity Tier One Capital, Systematic Risk Requirement Common Equity Tier One Capital, Systematic Risk Requirement Disclosure of net defined benefit liability (asset) [line items] Disclosure of net defined benefit liability (asset) [line items] Condensed consolidated income statements Statement of profit or loss and other comprehensive income [abstract] SC Germany S.A., Compartment Consumer 2025-2 SC Germany S.A., Compartment Consumer 2025-2 [Member] SC Germany S.A., Compartment Consumer 2025-2 Discount rate Discount rate applied to cash flow projections Change in scope of consolidation Increase (decrease) through transfers and other changes, intangible assets other than goodwill Subordinated issue, interest rate Interest rate Subordinated Issue, Interest Rate The interest rate on subordinated issues. Reserves or accumulated losses in joint venture investments Reserves Or Accumulated Losses In Joint Ventures Investments A component of other reserves within equity representing reserves or accumulated losses in joint ventures investments. Disclosure of information for cash-generating units [table] Disclosure of information for cash-generating units [table] Sale of ordinary shares in subsidiary (in shares) Sale Of Ordinary Shares In Subsidiary, Shares Sale Of Ordinary Shares In Subsidiary, Shares Disclosure of nature and extent of risks arising from financial instruments [table] Disclosure of nature and extent of risks arising from financial instruments [table] BDO BDO [Member] BDO Financial guarantees granted Guarantees Financial guarantee contracts [member] Options cancelled (net) or not exercised (in GBP per share) Weighted average exercise price of share options forfeited in share-based payment arrangement Long-term metric achievement percentage Variable Remuneration, Deferred Payment, Long-Term Metric Achievement, Percentage Variable Remuneration, Deferred Payment, Long-Term Metric Achievement, Percentage Other financial assets and liabilities Gains (Losses) On Financial Assets And Liabilities Not Measured At Fair Value Through Profit Or Loss Other Than Those Measured At Amortised Cost, Net Net amount of gains or losses on financial assets and liabilities not measured at fair value through profit or loss other than those measured at amortised cost. TLTRO III Targeted Long-Term Refinancing Operation III [Member] Targeted Long-Term Refinancing Operation III Credit default swaps Credit Default Swap1 [Member] Credit Default Swap [Member] Non-adjusting events after reporting period [axis] Non-adjusting events after reporting period [axis] EQ Options EQ Options [Member] EQ Options Volvo Car Financial Services UK Limited Volvo Car financial services UK ltd. [Member] Volvo Car financial services UK ltd. Non-controlling interest, other elements Non-controlling Interest Excluding Accumulated Other Comprehensive Income [Member] This member stands for equity, excluding accumulated other comprehensive income, in a subsidiary not attributable, directly or indirectly, to the parent. References Héctor Grisi Hector Grisi [Member] Hector Grisi Exchange differences, net Disclosure of effect of changes in foreign exchange rates [text block] Changes in the fair value of equity instruments measured at fair value through other comprehensive income (hedged item) Changes In The Fair Value Of Equity Instruments Measured At Fair Value Through Other Comprehensive Income (Hedged Item) Changes In The Fair Value Of Equity Instruments Measured At Fair Value Through Other Comprehensive Income (Hedged Item) Non-current assets classified as held for sale Other Reserves, Non-Current Assets Held For Sale That May Be Reclassified To Profit Or Loss, Net Of Tax Other Reserves, Non-Current Assets Held For Sale That May Be Reclassified To Profit Or Loss, Net Of Tax Issuance by Banco Santander S.A. in February 2018 Issuance By Banco Santander S.A. In February 2018 [Member] This member stands for issuance by Banco Santander S.a. in February 2018. Intangible assets and goodwill [abstract] Other long term employee benefits Long term employee benefits Other Long Term Employee Benefits Provision [Member] This member represents the provision for other long term employee benefits. Number of credit institutions included in reference group Number Of Credit Institutions Included In Reference Group Number of credit institutions included in reference group. Foreclosed assets Foreclosed Assets [Member] Assets foreclosed (repossessed) by the entity. Legal proceedings provision Legal proceedings provision [member] 2029 Later than three years and not later than four years [member] Financial liabilities offset in the consolidated balance sheets Net financial liabilities subject to offsetting, enforceable master netting arrangements or similar agreements in statement of financial position [abstract] Argentine peso Argentina, Pesos EUR/USD Euro And United States Dollar [Member] Euro And United States Dollar Consolidation reserves attributable to the Bank Consolidation Reserve A component of equity representing reserves for consolidation. Banco Santander, S.A., September 2021 Issuance By Banco Santander S.A. In September 2021 [Member] Issuance By Banco Santander S.A. In September 2021 Other operating expense Miscellaneous other operating expense Schedule of direct risk exposure to bank's directors and the guarantees provided Schedule of exposure to risk Summary quantitative data about entity's exposure to risk [text block] Abroad Group Foreign countries [member] Assets and liabilities classified as held for sale [axis] Assets and liabilities classified as held for sale [axis] Repos/Reverse Repos Repos/Reverse Repos [Member] Repos/Reverse Repos Miscellaneous liabilities [abstract] Miscellaneous liabilities [abstract] Income tax relating to items that will not be reclassified Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss Gross variable remuneration benchmark threshold General Threshold Of Variable Remuneration In Which Deferred The threshold trigger amount of variable remuneration or bonus, in which will be deferred over a specified period and paid in shares. The Northern Trust The Northern Trust [Member] The Northern Trust Other Non Residential Property Collateral [Member] This member stands for collateral in the form of non-residential property. Joint ventures [axis] Joint ventures [axis] Schedule of exchange differences included in other comprehensive income that may be reclassified to profit or loss Disclosure Of Other Comprehensive Income Exchange Differences In Foreign Operations That May Be Reclassified To Profit Or Loss [Table Text Block] The schedule of exchange differences of the effective portion of the hedge of net investments in foreign operations included in other comprehensive income that may be reclassified to profit or loss. Cash, cash balances at central banks and other deposits on demand Cash and reserves available at central banks Cash Cash Balance At Central Banks And Other Deposits On Demand [Member] This member stands for cash, cash balances at Central Banks and other deposits on demand. Below BBB IFRS Standard Poors Below BBB Rating [Member] BBB- credit rating as defined by the external credit rating agency, Standard & Poor's. Intangible assets Proceeds from sales of intangible assets, classified as investing activities Disclosure of risk management strategy related to hedge accounting [line items] Disclosure of risk management strategy related to hedge accounting [line items] Number of employees - undeclared Number Of Undeclared Employees Number Of Undeclared Employees Number of judgments rendered Number Of Judgments Rendered Number Of Judgments Rendered Customers Loans and advances: customers Loans And Advances, Customers [Member] This member represents the loans and advances made to customers, including money market operations through central counterparties. Excludes loans and advances at central banks and credit institutions. Growth rate Growth Rate, Measurement Input [Member] Growth Rate, Measurement Input VaR confidence level, percent VaR percentage Value At Risk, Confidence Level Percentage The specified confidence level percentage used to measure potential loss exposure due to the effects of future market movements on value at risk. Financial liabilities at amortized cost Adjustments for increase (decrease) in financial liabilities measured at amortised cost Deferred tax liabilities Deferred tax liabilities at beginning of period Deferred tax liabilities at end of period Deferred tax liabilities FX Options Foreign Exchange Options [Member] Foreign Exchange Options Schedule of fair value of derivatives by type of risk Disclosure Of Notional Amount And Market Value Of Trading Derivatives [Table Text Block] Disclosure of notional amount and market value of trading derivatives Geographical [Axis] Geographical [Axis] Subordinated liabilities, preference shares Subordinated Liabilities, Preference Shares [Member] Preference shares classified as subordinated liabilities. Property, plant and equipment including right-of-use assets [axis] Property, plant and equipment including right-of-use assets [axis] Income tax recovered/(paid) Income tax (receipts)/payments Reimbursements/payments of income tax Income taxes paid (refund), classified as operating activities Other material actuarial assumptions Other material actuarial assumptions Carrying amount Not At Fair Value [Member] Measured using a method that is not at fair value. Other Tangible Assets Other Tangible Assets [Member] Other Tangible Assets More than 60% and less than or equal to 80% LTV 60 To 80 Percent [Member] Loan-to-value (LTV) ratio from 60 to 80%. (-) Own shares Treasury shares [member] Investment properties Investment property Net issuances, redemptions and repurchases Subordinated Liabilities, Net Issuances, Redemptions And Repurchases The net amount of issuances, redemptions and repurchases for subordinated liabilities. (Charge)/Credit to asset and liability valuation adjustments Deferred Tax Relating To Items Credited Directly To Asset Valuation Adjustments The amount of deferred tax related to items credited to asset valuation adjustments. Subsidiaries and joint ventures Non-controlling interests Disclosure of subsidiaries [line items] Assets and liabilities [axis] Assets and liabilities [axis] B) Not designated elements - linked to a transaction Not Designated Items, By Transaction [Member] Not Designated Items, By Transaction BPA growth objective, target Variable Remuneration, Deferred Payment, BPA Growth, Target Variable Remuneration, Deferred Payment, BPA Growth, Target Capital losses by valuation Reserve Of Gains And Losses From Investment In Equity Instruments, Accumulated Losses The portion of the reserve of gains and losses from investments in equity instruments that represents accumulated revaluation losses. Application of amortization and impairment Application Of Amortisation And Impairment, Intangible Assets Other Than Goodwill The amount of application of amortisation or impairment of intangible assets other than goodwill. Other companies Other Companies [Member] Represents information pertaining to other subsidiary companies of the entity. Compensation received , life and health insurance contribution Key Management Personnel Directors Compensation Received, Life And Health Insurance Contribution Key Management Personnel Directors Compensation Received, Life And Health Insurance Contribution Subordinated liabilities (note 23) Interest Expense On Debt Instruments Issued Subordinated Liabilities The amount of interest expense for the accruals on subordinated liabilities. Percentage of share capital required to be maintained in the legal reserve Percentage of share capital required to be maintained in the legal reserve before annual transfers can be discontinued Percentage Of Share Capital Required To Be Maintained In Legal Reserve Percentage of share capital required to be maintained in the legal reserve before annual required transfers can be discontinued. Publicly listed Listed [Member] This member stands for equity instruments that are listed on exchanges. Own equity instruments Description of accounting policy for treasury shares [text block] Bills Credit Related Fee And Commission Income Bills The amount of income recognised from credit-related fees and commissions from bills. Javier Botín Javier Botin-Saenz De Sautuola [Member] Javier Botin-Saenz De Sautuola Percentage used to adjust sensitivity analysis Percentage Of Reasonably Possible Increase (Decrease) In Assumption Percentage Of Reasonably Possible Increase (Decrease) In Assumption For own use Property, Plant And Equipment Purchased For Own Use [Member] Member represents property, plant and equipment that are purchased for the company's own use. Property, plant and equipment including right-of-use assets [domain] Property, plant and equipment including right-of-use assets [domain] Instruments matured but not consolidated at beginning of period (in shares) Number Of Shares Matured But Not Consolidated In Share-Based Payment Arrangement Number Of Shares Matured But Not Consolidated In Share-Based Payment Arrangement Other provisions Miscellaneous other provisions [member] Senior secured debt Senior Secured Debt [Member] Senior Secured Debt [Member] IR option pricing model Interest Rate Option Pricing Model [Member] Interest Rate Option Pricing Model Profit/(loss) after tax from discontinued operations Net profit from discontinued operations Profit from discontinued operations (net) Profit (loss) from discontinued operations LTV less than 70% LTV Less Than 70 Percent [Member] LTV Less Than 70 Percent Nominal perpetual growth rate Growth rate used to extrapolate cash flow projections Level 1 additional capital coefficient (AT1) Tier One Capital In Excess Of Common Equity Tier One Capital, Percentage Of Risk Weighted Assets The amount of Tier 1 capital beyond that included in Common Equity Tier 1 capital divided by risk-weighted assets, which are assets that are weighted for credit risk. Accumulated impairment Impairment losses Accumulated impairment [member] Banco Santander (Brasil) S.A. Banco Santander Brasil SA [Member] Represents information pertaining to Banco Santander (Brasil) S.A., a subsidiary of the entity. Rest of America Rest Of America [Member] Rest Of America Memorandum items Disclosure of commitments and contingent liabilities [text block] VaR Market Risk Evaluated Using Value At Risk Metric [Member] Information pertaining to market risk evaluated using Value at Risk (VaR) metric. Forwards on interest rate and variable income Forwards On Interest Rate And Variable Income [Member] Forwards On Interest Rate And Variable Income Tax Reform [Axis] Tax Reform [Axis] Tax Reform Disclosure of detailed information about property, plant and equipment Disclosure of detailed information about property, plant and equipment [text block] Accumulated retained earnings Disclosure of reserves within equity [text block] Associates And Joint Ventures [Domain] Equity Method Investments [Domain] Equity Method Investments Classes of Deferred Tax Assets [Domain] Classes Of Deferred Tax Assets [Domain] Classes of Deferred Tax Assets [Domain] Inflation Swap Rate Inflation Swap Rate, Measurement Input [Member] Inflation Swap Rate, Measurement Input Annual interest rate (as a percent) Borrowings, interest rate CASH FLOWS FROM INVESTING ACTIVITIES Cash flows from (used in) investing activities Trading derivatives Disclosure of derivative financial instruments [text block] Reverse repurchase agreements Reverse Repurchase Agreements [Member] This member stands for financial assets as reverse repurchase agreements. Loans And Advances To Customers Table [Line Items] Loans And Advances To Customers Table [Line Items] Loans And Advances To Customers Table [Line Items] Profit (loss) from continuing operations (PPC net) Profit (loss) from continuing operations (net of non-controlling interests and CCP) Profit (loss) from continuing operations attributable to ordinary equity holders of parent entity, used in calculating diluted earnings per share Gross loans and advances to customers Gross Loans And Advances To Customers [Member] Gross Loans And Advances To Customers Staff costs Total staff costs Employee benefits expense Total eligible capital Eligible Capital The amount of total eligible capital as defined in the regulations. Members of the executive committee Executive committee Executive Committee1 [Member] This member stands for those persons serving as members of the executive committee of the board of directors. Current assets Current assets Stage 2 and 3 Lifetime expected credit losses [member] HEDGING DERIVATIVES Hedging derivatives (assets) Hedging derivatives Derivative financial assets held for hedging Disclosure of operating segments [table] Disclosure of operating segments [table] Deferred multiyear objectives variable remuneration plan second and third cycles Deferred Multiyear Objectives Variable Remuneration Plan Second And Third Cycles [Member] Information pertaining to the Deferred Multiyear Objectives Variable Remuneration Plan, second and third cycles (2017 and 2018). Total for all subsidiaries Total for all subsidiaries [member] VaE confidence level, percent Value At Earnings, Confidence Level Percentage The specified confidence level percentage used to measure potential profits due to the effects of future market movements. Construction and property development Construction And Property Development Loans [Member] This member stands for construction and property development loans. Flexible loans, mortgage portfolio, percentage Flexible Loans, Mortgage Portfolio, Percentage Flexible Loans, Mortgage Portfolio, Percentage Equities VaR Equities Equity price risk [member] To pre-retirees employees Defined Benefit Obligation To Pre-Retirees At Present Value The present value, without deducting any plan assets, of expected future payments required to settle the obligation to pre-retirees resulting from employee service in the current and prior periods. Segments [axis] Segments [axis] Types of risks [axis] Types of risks [axis] Equity instruments Disclosure Of Equity Financial Instruments [Text Block] The entire disclosure for equity financial instruments. Repaid By Banco Santander S.A. In August 2025, ISIN XS1548444816 Repaid By Banco Santander S.A. In August 2025, ISIN XS1548444816 [Member] Repaid By Banco Santander S.A. In August 2025, ISIN XS1548444816 Auto ABS UK Loans PLC Auto ABS UK Loans PLC [Member] Auto ABS UK Loans PLC Other assets Other Assets, Policy [Policy Text Block] Disclosure of accounting policy regarding assets classified as other. Mortgage loans denominated in, or indexed to, CHF Mortgage Loans, Denominated In/Indexed To Swiss Francs Mortgage Loans, Denominated In/Indexed To Swiss Francs Credit risk with customers Exposure To Credit Risk, Lending, Guarantees And Documentary Credits The amount that represents exposure to credit risk for lending to customers, guarantees and documentary credits, which is less than the maximum exposure to credit risk. Margin Of A Reference Portfolio Margin Of A Reference Portfolio [Member] Margin Of A Reference Portfolio Deferred multiyear objectives variable remuneration plan seventh cycle Deferred Multiyear Objectives Variable Remuneration Plan Seventh Cycle [Member] Deferred Multiyear Objectives Variable Remuneration Plan Seventh Cycle Marketable Debt Securities [Abstract] Marketable Debt Securities [Abstract] N/A. Shareholders' equity Disclosure Of Shareholders' Equity [Text Block] The disclosure for shareholders' equity. Other debt securities Debt Securities, Other [Member] Debt Securities, Other Options exercised (in GBP per share) Weighted average exercise price of share options exercised in share-based payment arrangement 2023 Program, Second 2023 Program, Second [Member] 2023 Program, Second Credit impaired Credit Impaired [Member] This member stands for financial instruments measured at amortised cost and classified as doubtful, whether due to counterparty arrears or because there are reasonable doubts as to their repayment under the contractual terms. Financial instruments include, but are not limited to, financing receivables, loans, debt, and investments. HEDGING DERIVATIVES Hedging derivatives (liabilities) Hedging derivatives Derivative financial liabilities held for hedging Bonds and debentures outstanding Bonds And Debentures Outstanding [Member] Represents bonds and debentures outstanding. Financial assets at amortized cost Financial assets at amortised cost, category [member] Net inclusion of entities in the Group Subordinated Liabilities, Net Inclusion Of Entities Subordinated Liabilities, Net Inclusion Of Entities Nominal value per share (in euro per share) Par value per share Assets And Liabilities Classified As Held For Sale [Table] Assets And Liabilities Classified As Held For Sale [Table] Schedule reflecting gains or losses on assets held for sale not classified as discontinued operations. Unsettled financial transactions Unsettled Financial Transactions Liability The amount of unsettled financial transactions recognized as a liability. Disclosure of maturity analysis of operating lease payments Disclosure of maturity analysis of operating lease payments [text block] Deposits Deposit Liability The amount of liability for deposits held by the entity. Amendment Flag Amendment Flag NSFR ratio (%) Net Stable Funding Ratio Net Stable Funding Ratio Expense of restructuring activities Expense of restructuring activities Separate management entities [domain] Separate management entities [domain] Central banks and credit institutions Loans And Advances, Central Banks And Credit Institutions [Member] Information pertaining to loans and advances from central banks and credit institutions. Condensed Income Statements, Captions [Line Items] Condensed Income Statements, Captions [Line Items] Non-controlling interests Disclosure of non-controlling interests [text block] Post-employment benefits, other long-term employee benefits and termination benefits Description of accounting policy for employee benefits [text block] Non-controlling interest, other comprehensive income Accumulated Other Comprehensive Income Attributable To Non-controlling Interests [Member] This member stands for accumulated other comprehensive income in a subsidiary not attributable, directly or indirectly, to the parent. References Reserves of entities accounted for using the equity method Reserve For Equity Method Investments A component of equity representing reserves of entities accounted for using the equity method. Schedule of other operating income and other operating expenses Disclosure Of Other Operating Income Expense [Table Text Block] The tabular disclosure of other operating income or expense. Share Buyback Program [Axis] Share Buyback Program [Axis] Share Buyback Program Deposits from central banks and credit institutions Deposits From Central Banks And Credit Institutions [Abstract] Deposits From Banks [Abstract] Globally systemically important entity percentage Common Equity Tier One Capital Ratio, Global Systemically Important Entity Additional percentage of Common Equity Tier One Risk-based Capital to total risk-weighted assets required for an entity defined as a systemically important financial institution (SIFI), as defined by regulatory framework. Temporary difference, unused tax losses and unused tax credits [axis] Temporary difference, unused tax losses and unused tax credits [axis] Method of assessment of expected credit losses [domain] Method of assessment of expected credit losses [domain] Gain or losses on financial assets and liabilities not measured at fair value through profit or loss, net Gain or losses on financial assets and liabilities not measured at fair value through profit or loss, net Gains Losses On Financial Assets And Liabilities Not Measured At Fair Value Through Profit Or Loss Net Net amount of gains or losses on financial assets and liabilities not measured at fair value through profit or loss, net. Amount of DVA Accumulated increase (decrease) in fair value of financial liability, attributable to changes in credit risk of liability Equity risk Market Value Of Equity [Member] This member stands for the type of risk that the fair value or future cash flows of a financial instrument will fluctuate because of changes in market interest rates that affect the market value of equity. Interest rate and exchange rate risk Interest rate and exchange rate risk Interest Rate And Exchange Rate Risk [Member] Information pertaining to risks related to interest rates and exchange rates/currency. Cards Assigned Third Party Commissions Cards Expense The amount of commissions assigned to third parties from cards. One to three months 1 to 3 months Later than one month and not later than three months [member] Profit Distribution [Line Items] Schedule Of Profit Distribution [Line Items] Profit Distribution [Line Items] Index and securities options Index And Securities Options [Member] This member stands for index and securities options. Provisions for defined benefits Provision For Defined Benefits Provisions for defined benefits. Pensionable base, expressed as a percent of fixed, number of previous bonuses Defined Benefit Obligation, Pensionable Base, Basis, Number Of Previous Bonuses Defined Benefit Obligation, Pensionable Base, Basis, Number Of Previous Bonuses Carrying amount of hedged items - Assets Hedged item, assets Assets foreclosed Foreclosed Properties [Abstract] No definition available. Issuance by Banco Santander Brasil in September 2024 Issuance By Banco Santander Brasil In September 2024 [Member] Issuance By Banco Santander Brasil In September 2024 Previously stated Previously stated [member] Consolidated Entities [Axis] Consolidated Entities [Axis] Sustainability metric, achievement rate Variable Remuneration, Deferred Payment, Sustainability Metric, Achievement Rate Variable Remuneration, Deferred Payment, Sustainability Metric, Achievement Rate European Union IFRS European Union [Member] Economic and political union of member states, located primarily in Europe. More than 10 years Later than ten years [member] Loans and advances to central banks and credit institutions Loans And Advances To Central Banks And Credit Institutions [Abstract] Loans and Advances to Banks [Abstract] Appreciation variation (as a percent) Percentage Of Reasonably Possible Appreciation Of Entity's Functional Currency The reasonably possible percentage of the appreciation of entity's functional currency used to determine effect on the consolidated equity. Detail of gains (losses) on disposal of assets not classified as non-current assets held for sale Schedule Of Gains (Losses) On Disposal Of Assets Not Classified As Non-Current Assets Held For Sale [Table Text Block] The tabular disclosure of gains (losses) on disposal of assets not classified as held for sale. Antonio Weiss Antonio Francesco Weiss [Member] Antonio Francesco Weiss Additional provisions charged to income statement Additional provisions, other provisions Tax losses and tax credits Unused Tax Losses And Tax Credits [Member] This member stands for tax losses and credits that have been incurred and are carried forward for use against future taxable profit. Changes in the fair value of financial liabilities measured at fair value through profit or loss attributable to changes in credit risk Reserve of change in fair value of financial liability attributable to change in credit risk of liability Provision (release) of provision corresponding to results from commitments and contingent risks Provision (Release) Corresponding To Results From Commitments And Contingent Risks Provision (Release) Corresponding To Results From Commitments And Contingent Risks Actuarial assumption of growth Actuarial Assumption Of Growth [Member] Actuarial Assumption Of Growth Number of business lines, commercial segment Number Of Business Lines, Commercial Segment Number Of Business Lines, Commercial Segment Restricted reserves Restricted Reserves A component of equity representing reserves restricted as to usage. Mortgage-backed bonds average maturities Mortgage Backed Bonds Average Maturity Represents the average maturity for mortgage-backed bonds. 2019 variable remuneration Share Based Variable Remuneration Award 2019 [Member] Share Based Variable Remuneration Award 2019 Currency [Axis] Currency [Axis] Number of remuneration components Number Of Remuneration Components The number of components included in remuneration of directors. Treasury shares, number of shares transferred through donations (in shares) Treasury Shares, Number Of Shares Transferred Through Donations Treasury Shares, Number Of Shares Transferred Through Donations Residual maturity periods Description Of Accounting Policy For Residual Maturity Periods [Policy Text Block] The description of the entity's accounting policy for residual maturity periods and average interest rates. Period of time the employee contributions are deducted from their net monthly pay for the voluntary Sharesave Scheme Period Of Voluntary Sharesave Scheme Monthly Employee Contributions Period of time the employee contributions are deducted from their net monthly pay for the voluntary Sharesave Scheme. Disclosure of terms and conditions of share-based payment arrangement [table] Disclosure of terms and conditions of share-based payment arrangement [table] Property, plant and equipment for own use Property Plant And Equipment For Own Use [Abstract] n/a Credit impairment of financial instruments [domain] Credit impairment of financial instruments [domain] Number of persons Number of participants of retirement benefit plan receiving benefits Effective tax rate Average effective tax rate E) Net increase/(decrease) in cash and cash equivalents Increase (Decrease) In Cash And Cash Equivalents After Effect Of Foreign Exchange Rates, Discontinued Operations Increase (Decrease) In Cash And Cash Equivalents After Effect Of Foreign Exchange Rates, Discontinued Operations Vehicles Vehicles [member] Provision for customer remediation Provision For Customer Remediation [Member] This member stands for provision for customer remediation. 2018 variable remuneration Share Based Variable Remuneration Award 2018 [Member] Share Based Variable Remuneration Award2018 [Member] Consolidation Items [Axis] Consolidation Items [Axis] Schedule of basic and diluted earnings per share Earnings per share [text block] Loans and advances Loans And Advances [Member] This member stands for the financial instruments classified as loans and advances. These include the debit balances of all credit and loans granted by the entity, other than those represented by securities, as well as finance lease receivables and other debit balances of a financial nature in favour of the Group, such as checks drawn on credit institutions, balances receivable from clearing houses and settlement agencies for transactions on the stock exchange and organized markets, bonds given in cash, capital calls, fees and commissions receivable for financial guarantees and debit balances arising from transactions not originating in banking transactions and services, such as the collection of rentals and similar items. They are classified, on the basis of the institutional sector to which the debtor belongs, into Central Banks, Credit institutions, and Customers. SME Loans To Small And Medium Sized Enterprises [Member] Loans To Small And Medium Sized Enterprises Mortgage-backed securities average maturities Mortgage Backed Securities Average Maturity Represents the average maturity for mortgage-backed securities. Property derivatives Property Derivatives [Member] Property Derivatives Intangible assets other than goodwill [abstract] Option pricing model Option pricing model [member] Disclosure of detailed information about property, plant and equipment [table] Disclosure of detailed information about property, plant and equipment [table] Disclosure of detailed information about property, plant and equipment [table] Memorandum Items Memorandum Items [Axis] Memorandum Items Intangible assets Purchase of intangible assets, classified as investing activities Provisions or reversal of provisions, net Defined Benefit Plans, Provisions (Reversal), Net Defined Benefit Plans, Provisions (Reversal), Net T2-excesses - subsidiaries Excess Tier Two Risk Based Capital, Subsidiaries The amount by which the company's Tier 2 Risk Based Capital exceeds the minimum required for capital adequacy purposes attributable to subsidiaries. Impairment losses since time of foreclosure Accumulated Impairment Since Initial Impairment [Member] This member represents portion of accumulated impairment recognized since initial foreclosure. Percentage of total sovereign risk Percentage Of Total Sovereign Risk The percentage of total sovereign risk. Internal credit grades [axis] Internal credit grades [axis] Other Measurement Input Other Measurement Input [Member] Other Measurement Input State Street Bank State Street Bank [Member] Represents information pertaining to State Street Bank