Motor finance commission arrangements Motor Finance Commission Arrangements [Member] Motor Finance Commission Arrangements Other comprehensive (loss)/income that may be recycled to profit or loss: Components of other comprehensive income that will be reclassified to profit or loss, net of tax [abstract] Net derivative financial instruments Derivatives [member] Total assets Beginning balance, financial assets Ending balance, financial assets Financial assets, at fair value Disclosure of contingent liabilities [line items] Disclosure of contingent liabilities [line items] Interest and similar expense Interest expense Statistical Measurement [Domain] Statistical Measurement [Domain] Commitments and Contingent Liabilities [Axis] Commitments and Contingent Liabilities [Axis] Commitments and Contingent Liabilities Currency translation reserve Reserve of exchange differences on translation [member] Dividends paid on ordinary shares Ordinary shares Dividends paid, ordinary shares Increase (decrease) in other provisions Increase (decrease) in other provisions Levels of fair value hierarchy [domain] Levels of fair value hierarchy [domain] Financial assets at amortised cost Financial assets at amortised cost, class [member] Profit before Impairment Profit before Impairment Profit (Loss) From Operating Activities Before Impairment Loss (Reversal Of Impairment Loss) Recognised In Profit Or Loss Profit (Loss) From Operating Activities Before Impairment Loss (Reversal Of Impairment Loss) Recognised In Profit Or Loss Operating expenses Operating expense Assets and liabilities [domain] Assets and liabilities [domain] Classes of share capital [axis] Classes of share capital [axis] Of which inter-segmental income/(expense) Elimination of intersegment amounts [member] Transfers into Level 3 of fair value hierarchy, assets (liabilities), net Transfers Into Level 3 Of Fair Value Hierarchy, Assets (Liabilities), Net The amount of transfers of assets less liabilities into Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]] Later than two years and not later than three years Later than two years and not later than three years [member] Dividends paid on preference shares and other shareholders equity Preference shares Dividends paid, other shares Originated and sold to third parties by Acquired Subsidiary Originated And Sold To Third Parties By Acquired Subsidiary [Member] This member stands for sales of loans originated and sold to third parties by mortgage originator affiliates of an entity that the Group acquired in 2007 (Acquired Subsidiary). Total equity Beginning balance, equity Ending balance, equity Equity Equity Disposals Decrease Through Disposal, Exposure To Credit Risk On Loan Commitments And Financial Guarantee Contracts Decrease Through Disposal, Exposure To Credit Risk On Loan Commitments And Financial Guarantee Contracts Other equity instruments Other equity interest Sales, fair value measurement, assets Sales, fair value measurement, assets Total commitments and contingent liabilities Total Commitments and Contingent Liabilities [Member] Total Commitments and Contingent Liabilities Issues, fair value measurement, assets (liabilities), net Issues, Fair Value Measurement, Assets (Liabilities), Net The increase in fair value measurement of assets and liabilities resulting from issues of those assets and liabilities. [Refer: At fair value [member]] Reverse repurchase agreements Reverse Repurchase Agreements [Member] This member stands for reverse repurchase agreements. Disclosure of detailed information about borrowings [table] Disclosure of detailed information about borrowings [table] Purchases, fair value measurement, assets (liabilities), net Purchases, Fair Value Measurement, Assets (Liabilities), Net The increase in the fair value measurement of assets and liabilities resulting from purchases of those assets and liabilities. [Refer: At fair value [member]] Financial assets at fair value through profit or loss, category trading Financial Assets At Fair Value Through Profit Or Loss, Category Trading [Member] This member stands for the financial assets at fair value through profit or loss category, located in trading income. [Refer: Financial liabilities at fair value through profit or loss] Number of separate lawsuits Number Of Separate Lawsuits Number Of Separate Lawsuits Goodwill and intangible assets Intangible assets and goodwill Statement of comprehensive income [abstract] Statement of changes in equity [line items] Statement of changes in equity [line items] Total subordinated liabilities Subordinated Liabilities, Including Those Designated At Fair Value Subordinated Liabilities, Including Those Designated At Fair Value Best Egg Inc Best Egg Inc [Member] Best Egg Inc Other assets Other assets Currency translation differences Other comprehensive income, before tax, exchange differences on translation of foreign operations Other comprehensive income/(loss) not recycled to profit or loss: Components of other comprehensive income that will not be reclassified to profit or loss, net of tax [abstract] Quoted market prices (Level 1) Level 1 of fair value hierarchy [member] Dividends proposed or declared before financial statements authorised for issue but not recognised as distribution to owners Dividends proposed or declared before financial statements authorised for issue but not recognised as distribution to owners Observable inputs (Level 2) Level 2 of fair value hierarchy [member] Onerous contracts Onerous contracts provision [member] Upside 1 Upside 1 [member] The upside 1 scenario. The favourable scenarios are calibrated to be symmetric to the adverse scenarios, subject to a ceiling calibrated to relevant recent favourable benchmark scenarios. Net derivative financial instruments Derivatives, Netting [Member] Derivatives, Netting Financial assets at fair value through the income statement Financial assets at fair value through profit or loss, category [member] Not past due Current [member] Statement of financial position [abstract] Trading portfolio liabilities Trading portfolio liabilities Trading portfolio liabilities Financial liabilities at fair value through profit or loss that meet definition of held for trading Other income Other income Other operating income (expense) Cover [Abstract] Defined benefit plans [axis] Defined benefit plans [axis] Exit price adjustments derived from market bid-offer spreads Exit Price Adjustments Derived From Market Bid-Offer Spreads [Member] This member stands for exit price adjustments derived from market bid-offer spreads. The methodology for determining the bid-offer adjustment for a derivative portfolio involves calculating the net risk exposure by offsetting long and short positions by strike and term in accordance with the risk management and hedging strategy. Interest and similar income Interest revenue calculated using effective interest method Financial liabilities designated at fair value Financial liabilities designated at fair value Financial liabilities at fair value through profit or loss, designated upon initial recognition or subsequently Adjustment for non-cash and other items Other adjustments for non-cash items Net fee and commission income Fee and commission income (expense) Floating Rate Notes (ZAR) Floating Rate Notes (ZAR) [Member] Floating Rate Notes (ZAR) Transfers into Level 3 of fair value hierarchy, assets Transfers into Level 3 of fair value hierarchy, assets Deferred tax assets Deferred tax assets Opening balance Ending balance Exposure to credit risk on loan commitments and financial guarantee contracts Sales, fair value measurement, liabilities Sales, fair value measurement, liabilities Private equity investments Private Equity Investments [Member] This member stands for private equity investments. Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period Transfers out of Level 2 into Level 1 of fair value hierarchy, assets held at end of reporting period Transfers to Stage 3 Transfers To Stage Three [Member] This member stands for transfers into Stage three. Favorable changes, Equity Increase In Fair Value Measurement Due To Change In Multiple Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Recognised In OCI, After Tax, Assets (Liabilities) The amount of increase in the fair value measurement of assets (liabilities), recognised in other comprehensive income after tax, due to a change in multiple unobservable inputs to reflect reasonably possible alternative assumptions. [Refer: Tax income (expense)] Total comprehensive income for the period Comprehensive income Disclosure of movement in gross exposures and impairment allowance including provisions for loan commitments and financial guarantees Disclosure of credit risk [text block] Statement of changes in equity [abstract] Net losses transferred to net profit on disposal Reclassification Adjustments On Financial Assets Measured At Fair Value Through Other Comprehensive Income, Before Tax, On Disposal The amount of reclassification adjustments due to disposal of financial assets measured at fair value through other comprehensive income, before tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income] Retained earnings Retained earnings Measurement [domain] Measurement [domain] Basis of preparation Disclosure of basis of preparation of financial statements [text block] Disposals Decrease through derecognition, financial assets Barclays US Consumer Bank Barclays US Consumer Bank [Member] Barclays US Consumer Bank Preference shares, dividend rate Preference Shares, Interest Rate Preference Shares, Interest Rate 5-year averages Five Year Averages [Member] Average basis represents the average quarterly value of variables in the 20 quarter period with GDP and HPI based on yearly average and quarterly CAGRs respectively. Disclosure of detailed information about financial instruments [line items] Disclosure of detailed information about financial instruments [line items] Document Fiscal Period Focus Document Fiscal Period Focus Other Other Repayments (Proceeds) Of Borrowings, Classified As Financing Activities The cash inflow from and outflow to settle other borrowings, classified as financing activities. Civil Actions In Respect Of VRDO - Private Plaintiffs Civil Actions In Respect Of VRDO - Private Plaintiffs [Member] Civil Actions In Respect Of VRDO - Private Plaintiffs Total assets Total assets Assets Types of risks [domain] Types of risks [domain] Transfers out of Level 1 into Level 2 of fair value hierarchy, liabilities held at end of reporting period Transfers out of Level 1 into Level 2 of fair value hierarchy, liabilities held at end of reporting period Transactional Transactional Banking Services [Member] This member stands for fees fees from service charges on deposit account, cash management services and transactional processing fees. These fees include such items as ATM fees, wire transfer fees, balance transfer fees, overdraft or late fees and foreign exchange fees, among others. Repurchase agreements and other similar secured borrowing at amortised cost Repurchase agreements and other similar secured borrowing Repurchase agreements and cash collateral on securities lent Derivative financial instruments Derivative financial instruments Derivative financial assets Credit risk Credit risk [member] Investment property Investment property Investment property [member] Shareholders of the parent Profit (loss), attributable to ordinary equity holders of parent entity, used in calculating basic earnings per share Issues, fair value measurement, liabilities Issues, fair value measurement, liabilities Types of interest rates [axis] Types of interest rates [axis] Trading portfolio assets Financial assets at fair value through profit or loss, classified as held for trading Comparison of carrying amounts and fair values for assets and liabilities not held at fair value Disclosure Of Carrying Amounts And Fair Values For Assets And Liabilities Not Held At Fair Value [Table Text Block] The tabular disclosure of the fair value of financial assets and liabilities measured at amortised cost. Financial assets at fair value through the income statement Financial assets at fair value through profit or loss Subordinated liabilities Disclosure of borrowings [text block] Geographical areas [axis] Geographical areas [axis] Disclosure of fair value measurement of assets [abstract] Cash collateral and settlement balances Bank acceptance liabilities GDP Gross Domestic Product, Economic Variable [Member] This member stands for Gross Domestic Product, a key historic macroeconomic core variable. The GDP is compared against the forecast paths of the probability weights for each scenario, demonstrating the highest annual growth in the Upside scenarios; 5 year average in Baseline; lowest annual growth in Downside scenarios. Classes of other provisions [domain] Classes of other provisions [domain] Other reserves Other reserves [member] Litigation and conduct Litigation and conduct Losses on litigation settlements Assets By Function [Axis] Assets By Function [Axis] Assets By Function HMRC assessments concerning UK VAT HM Revenue & Customs (HMRC) Assessments Concerning UK Value Added Tax [Member] In March 2018 HMRC issued notices that have the effect of removing certain overseas subsidiaries that have operations in the UK from Barclays UK VAT group, in which group supplies between members are generally free from VAT. Limit management and final repayments Decrease through derecognition, exposure to credit risk on loan commitments and financial guarantee contracts Unemployment Unemployment, Economic Core Variable [Member] This member stands for unemployment, a key historic macroeconomic core variable. The unemployment is compared against the forecast paths of the probability weights for each scenario, demonstrating the lowest point in the Upside scenarios; 5 year average in Baseline; highest point in Downside scenarios. Management adjustments Management Adjustments [Member] Management Adjustments Net write-offs Impairment loss (reversal of impairment loss) recognised in profit or loss, loans and advances Unfavorable changes, Equity Decrease In Fair Value Measurement Due To Change In Multiple Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Recognised In OCI, After Tax, Assets (Liabilities) The amount of decrease in the fair value measurement of assets (liabilities), recognised in other comprehensive income after tax, due to a change in multiple unobservable inputs to reflect reasonably possible alternative assumptions. [Refer: Tax income (expense)] Total gains and losses in the period recognised in the income statement, assets (liabilities), net Gains (Losses) Recognised In Profit Or Loss, Fair Value Measurement, Assets (Liabilities), Net The gains (losses) recognised in profit or loss on the fair value measurement of assets and liabilities. [Refer: At fair value [member]] Disclosure of loans and advances at amortised cost by product Disclosure of provision matrix [text block] Assets and liabilities included in disposal group classified as held for sale Disclosure of non-current assets or disposal groups classified as held for sale [text block] Intangible assets Intangible assets other than goodwill Diversification effect Risk diversification effect [member] Retail credit cards Credit Cards, Retail [Member] Credit Cards, Retail Number of initial lawsuits amended Number Of Initial Lawsuits Amended Number Of Initial Lawsuit Amended Financial instruments at amortised cost, category Financial Instruments At Amortised Cost, Category [Member] This member stands for the financial instruments carried at amortised cost category. Segments [domain] Segments [domain] Cash and cash equivalents at beginning of the period Cash and cash equivalents at end of the period Cash and cash equivalents Issuances Proceeds from issue of subordinated liabilities Proceeds from issue of subordinated liabilities Head Office Unallocated amounts [member] Disclosure Of Assets And Liabilities Classified As Held For Sale [Line Items] Disclosure Of Assets And Liabilities Classified As Held For Sale [Line Items] Disclosure Of Assets And Liabilities Classified As Held For Sale [Line Items] Barclays Private Bank and Wealth Management Barclays Private Bank And Wealth Management [Member] Barclays Private Bank And Wealth Management Documentary credits and other short-term trade related transactions Documentary Credits And Other Short-Term Trade Related Transactions [Member] This member stands for documentary credits and other short-term trade related transactions. Number of legal challenges Number Of Legal Challenges Number Of Legal Challenges Disclosure of non-adjusting events after reporting period [line items] Disclosure of non-adjusting events after reporting period [line items] Assets Assets [abstract] Transfers into Level 3 of fair value hierarchy, liabilities Transfers into Level 3 of fair value hierarchy, liabilities Total liabilities and equity Equity and liabilities US UNITED STATES Assets By Function [Domain] Assets By Function [Domain] Assets By Function [Domain] Inflation risk Inflation Risk [Member] This member stands for the inflation risk factor. Business combinations [axis] Business combinations [axis] Fixed Rate Resetting Perpetual Subordinated Contingent Convertible Securities Fixed Rate Resetting Perpetual Subordinated Contingent Convertible Securities [Member] Fixed Rate Resetting Perpetual Subordinated Contingent Convertible Securities Provisions Provisions Disposal groups classified as held for sale Disposal groups classified as held for sale [member] Business combinations [domain] Business combinations [domain] 4.75% Non-Cumulative Callable Euro Preference Series 2 4.75% Non-Cumulative Callable Euro Preference Series 2 [Member] 4.75% Non-Cumulative Callable Euro Preference Series 2 Disclosure Of Assets And Liabilities Classified As Held For Sale [Table] Disclosure Of Assets And Liabilities Classified As Held For Sale [Table] Disclosure Of Assets And Liabilities Classified As Held For Sale Cash flow hedging reserve Cash flow hedges [abstract] Number of lawsuits subject to appeal Number Of Lawsuits Subject To Appeal Number Of Lawsuits Subject To Appeal Disclosure of reserves within equity [table] Disclosure of reserves within equity [table] 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] Reconciliation of changes in fair value measurement, assets [abstract] Reconciliation of changes in fair value measurement, assets [abstract] Total exchange and other adjustments Increase (decrease) through foreign exchange and other movements, financial assets Disclosure of defined benefit plans [abstract] Aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss Aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss Number of overseas subsidiaries denied VAT Grouping by the HMRC Number of Overseas Subsidiaries Denied VAT Grouping by HMRC Number of Overseas Subsidiaries Denied VAT Grouping by HMRC Increase in fair value measurement due to change in one or more unobservable inputs to reflect reasonably possible alternative assumptions, assets (liabilities) Increase In Fair Value Measurement Due To Change In One Or More Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Assets (Liabilities) The amount of increase in the fair value measurement of assets and liabilities due to a change in one or more unobservable inputs to reflect reasonably possible alternative assumptions. Other equity holders Adjustments to reconcile profit (loss) attributable to owners of parent to numerator used in calculating basic earnings per share Interest rate risk Interest rate derivatives Interest rate risk [member] Disclosure of initial application of standards or interpretations [abstract] Disclosure of initial application of standards or interpretations [abstract] Advisory Management And Advisory Services [Member] This member stands for fees from asset management services and advisory services related to mergers, acquisitions and financial restructuring. Credit impairment of financial instruments [axis] Credit impairment of financial instruments [axis] Fair value of financial instruments Disclosure of fair value of financial instruments [text block] Assets By Functions [Axis] Assets By Functions [Axis] Assets By Functions Reserves within equity [axis] Reserves within equity [axis] US residential and commercial mortgage-related activity and litigation US Residential And Commercial Mortgage-Related Activity And Litigation [Member] Various investigations and civil litigation relating to secondary market trading of US residential mortgage-backed securities (RMBS) and US commercial mortgage-backed securities (CMBS). Categories of financial liabilities [domain] Categories of financial liabilities [domain] Corporate loans Corporate debt Loans to corporate entities [member] Other movements Increase (decrease) through other changes, equity Commodity risk Commodity price risk [member] Related party transactions Disclosure of related party [text block] Classes of financial assets [domain] Classes of financial assets [domain] Number of economic scenarios Total Number Of Economic Scenarios To Calculate ECL Total Number Of Economic Scenarios To Calculate ECL Impairment allowance pre management adjustments Pre-Management Adjustments [Member] Pre-Management Adjustments RMBS repurchase requests RMBS Repurchase Requests [Member] This member stands for various US residential mortgage-backed securities loan-level representations and warranties (R&Ws). Impairment loss recognised in profit or loss, intangible assets and goodwill Impairment loss recognised in profit or loss, intangible assets and goodwill Performance guarantees, acceptances and endorsements Performance Guarantees, Acceptances And Endorsements [Member] This member stands for performance guarantees, acceptances and endorsements. Issues, fair value measurement, assets Issues, fair value measurement, assets Net trading income Trading income Trading income (expense) Significant unobservable inputs (Level 3) Level 3 of fair value hierarchy [member] Sales, fair value measurement, assets (liabilities), net Sales, Fair Value Measurement, Assets (Liabilities), Net The decrease in the fair value measurement of assets and liabilities resulting from sales of those assets and liabilities. [Refer: At fair value [member]] Issue and redemption of equity instruments Issue And Redemption Of Other Equity Instruments The increase (decrease) in equity resulting from the issue and exchange of other equity instruments. [Refer: Equity] Employee settled Barclays PLC shares scheme Increase (decrease) through share-based payment transactions, equity Goodwill recognised as of acquisition date Goodwill recognised as of acquisition date Value at risk Value at risk Currency translation movements Other comprehensive income, net of tax, exchange differences on translation of foreign operations Reconciliation of changes in fair value measurement, liabilities [abstract] Reconciliation of changes in fair value measurement, liabilities [abstract] Write-offs Decrease through write-off, financial assets Loans and advances at amortised cost Loans and advances at amortised cost Segment consolidation items [domain] Segment consolidation items [domain] Net assets (liabilities) at fair value through profit or loss, category other income Net Assets (Liabilities) At Fair Value Through Profit Or Loss, Category Other Income [Member] This member stands for the net assets (liabilities) at fair value through profit or loss category, located in other income. [Refer: Financial liabilities at fair value through profit or loss] Liabilities measured at fair value and issued with inseparable third-party credit enhancement [axis] Liabilities measured at fair value and issued with inseparable third-party credit enhancement [axis] Reverse repurchase and repurchase agreements Reverse Repurchase And Repurchase Agreements [Member] This member stands for securities purchased under resale agreements, securities sold under repurchase agreements, and other similar secured lending agreements. Disclosure of disaggregation of revenue from contracts with customers [line items] Disclosure of disaggregation of revenue from contracts with customers [line items] Not later than 30 days past due Not later than one month [member] Basis risk Basis Risk [Member] This member stands for the basis risk factor. Disclosure of non-current assets or disposal groups classified as held for sale Disclosure Of Assets And Liabilities Classified As Held For Sale [Table Text Block] Disclosure Of Assets And Liabilities Classified As Held For Sale Major ordinary share transactions Major ordinary share transactions [member] BDC Finance LLC BDC Finance LLC [Member] BDC Finance L.L.C. (BDC) has filed a complaint against Barclays Bank PLC alleging breach of contract in connection with a portfolio of total return swaps governed by an ISDA Master Agreement (collectively, the Agreement). Non-current assets or disposal groups classified as held for sale or as held for distribution to owners [abstract] Past due status [axis] Past due status [axis] Classification of assets as held for sale Classification of assets as held for sale [member] Financial assets Categories of financial assets [abstract] Other equity instruments Other equity interest [member] Effect of exchange rates on cash and cash equivalents Effect of exchange rate changes on cash and cash equivalents Net gains/(losses) due to fair value hedging Reclassification Adjustments On Financial Assets Measured At Fair Value Through Other Comprehensive Income, Before Tax, Due To Fair Value Hedging The amount of reclassification adjustments due to impairment of financial assets measured at fair value through other comprehensive income, before tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income] Net cash from operating activities Cash flows from (used in) operating activities Standby facilities, credit lines and other commitments Standby Facilities, Credit Lines And Other Commitments [Member] This member stands for standby facilities, credit lines and other commitments including forward starting reverse repurchase agreements. Disclosure of detailed information about financial instruments [table] Disclosure of detailed information about financial instruments [table] Geographical areas [domain] Geographical areas [domain] Document Fiscal Year Focus Document Fiscal Year Focus Own credit reserve Reserve of change in fair value of financial liability attributable to change in credit risk of liability [member] Decrease in fair value measurement due to change in one or more unobservable inputs to reflect reasonably possible alternative assumptions, assets (liabilities) Decrease In Fair Value Measurement Due To Change In One Or More Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Assets (Liabilities) The amount of decrease in the fair value measurement of assets and liabilities due to a change in one or more unobservable inputs to reflect reasonably possible alternative assumptions. Asset backed securities Securities, Asset Backed [Member] Securities, Asset Backed Individually assessed impairments Expected credit losses individually assessed [member] Levels of fair value hierarchy [axis] Levels of fair value hierarchy [axis] Types of interest rates [domain] Types of interest rates [domain] ECL movement Increase (decrease) in financial assets Increase (decrease) in financial assets Transfers out of Level 2 into Level 1 of fair value hierarchy, liabilities held at end of reporting period Transfers out of Level 2 into Level 1 of fair value hierarchy, liabilities held at end of reporting period Classes of other provisions [axis] Classes of other provisions [axis] Disclosure of credit risk exposure [table] Disclosure of credit risk exposure [table] Other liabilities Other liabilities Pension defined benefit plans Pension defined benefit plans [member] Issue of convertible instruments Issue of convertible instruments Loans and advances to customers Loans and advances to customers Issued debt Issued Debt [Member] Issued Debt Civil actions in respect of the US anti-terrorism act Civil Actions In Respect Of The US Anti-Terrorism Act [Member] Civil complaints against Barclays Bank PLC and other banks allege engagement in a conspiracy and violation of the US Anti-Terrorism Act (ATA). Cash collateral and settlements Cash Collateral And Settlements [Member] Cash Collateral And Settlements Fair value Not measured at fair value in statement of financial position but for which fair value is disclosed [member] Retirement benefit remeasurements Other comprehensive income, before tax, gains (losses) on remeasurements of defined benefit plans Sensitivity analysis of valuations using unobservable inputs Sensitivity analysis for types of market risk [text block] Deposits at amortised cost from banks Deposits from banks at amortised cost Entity Central Index Key Entity Central Index Key Other comprehensive loss that may be recycled to profit or loss Other comprehensive income that will be reclassified to profit or loss, net of tax Derivative financial instruments Derivative financial instruments Derivative financial liabilities Derivative financial liabilities Characteristics of defined benefit plans [axis] Characteristics of defined benefit plans [axis] Disclosure of credit risk exposure [line items] Disclosure of credit risk exposure [line items] Total income Operating Income Operating Income Valuation techniques used in fair value measurement [axis] Valuation techniques used in fair value measurement [axis] Ordinary shares Ordinary shares [member] Attributable to: Profit (loss), attributable to [abstract] Gross exposure Carrying amount Gross carrying amount [member] 1.125% Fixed Rate Resetting Subordinated Callable Notes (EUR) 1.125% Fixed Rate Resetting Subordinated Callable Notes (EUR) [Member] 1.125% Fixed Rate Resetting Subordinated Callable Notes (EUR) Derivative debit valuation adjustments Derivative Debit Valuation Adjustments [Member] This member stands for derivative debit valuation adjustment for the impact on fair value of the entoty's own credit quality. Net (losses)/gains from changes in fair value Gains (losses) on cash flow hedges, before tax Net assets (liabilities) [abstract] Net assets (liabilities) [abstract] Net fee and commission income Disclosure of fee and commission income (expense) [text block] Cash collateral and settlement balances Bank acceptance assets Net interest income Net interest income Interest income (expense) Reverse repurchase agreements and other similar secured lending at amortised cost Reverse repurchase agreements and other similar secured lending Reverse repurchase agreements and cash collateral on securities borrowed Total gains or losses recognised in OCI, assets Gains (losses) recognised in other comprehensive income including exchange differences, fair value measurement, assets Not later than one year Not later than one year [member] Method of assessment of expected credit losses [axis] Method of assessment of expected credit losses [axis] Current tax liabilities Current tax liabilities Transfers out of Level 3 of fair value hierarchy, liabilities Transfers out of Level 3 of fair value hierarchy, liabilities Transfers out of Level 3 of fair value hierarchy, liabilities Fee and commission income Fee and commission income Fee and commission income Stress horizon period Stress Horizon Period, ECL Stress Horizon Period, ECL Guarantees and letters of credit pledged as collateral security Guarantees And Letters Of Credit Pledged As Collateral Security [Member] This member stands for guarantees and letters of credit pledged as collateral security. Identifiable intangible assets recognised as of acquisition date Identifiable intangible assets recognised as of acquisition date Defined benefit plans other than multi-employer plans, state plans and plans that share risks between entities under common control Defined benefit plans other than multi-employer plans, state plans and plans that share risks between entities under common control [member] Disclosure of financial assets [line items] Disclosure of financial assets [line items] Trading portfolio liabilities Financial liabilities at fair value through profit or loss that meet definition of held for trading, category [member] Preference shares, principal outstanding Preference Shares, Principal Outstanding Preference Shares, Principal Outstanding Reconciliation of ECL movement to impairment charges for the period Disclosure of impairment loss and reversal of impairment loss [abstract] Changes in other operating assets and liabilities Other adjustments to reconcile profit (loss) Transfers out of Level 1 into Level 2 of fair value hierarchy, assets held at end of reporting period Transfers out of Level 1 into Level 2 of fair value hierarchy, assets held at end of reporting period Entity Registrant Name Entity Registrant Name Other products Other Financial Assets And Liabilities Group One [Member] This member stands for commercial real estate loans, funds and fund-linked products, asset backed loans, issued debt, commercial paper, government sponsored debt and investment property. Liabilities measured at fair value and issued with inseparable third-party credit enhancement [domain] Liabilities measured at fair value and issued with inseparable third-party credit enhancement [domain] Measurement [axis] Measurement [axis] Provisions Disclosure of provisions [text block] Statement of cash flows [abstract] Disclosure of financial assets [table] Disclosure of financial assets [table] Retail mortgages Mortgages [member] Type of measurement of expected credit losses [axis] Type of measurement of expected credit losses [axis] Civil actions in respect of USD LIBOR Civil Actions In Respect of USD LIBOR [Member] Civil Actions In Respect of USD LIBOR Floating interest rate Floating interest rate [member] Redemptions Redemption of subordinated debt Repayments of subordinated liabilities HPI House Price Index, Economic Core Variable [Member] This member stands for the House Price Index, a key historic macroeconomic core variable. The House Price Index is compared against the forecast paths of the probability weights for each scenario, demonstrating 5 year cumulative growth in Upside scenarios; 5 year average in Baseline; cumulative fall (peak-to-trough) in Downside scenarios. Underwriting and syndication Underwriting, Syndication And Commitment Fees [Member] This member stands for fees which are earned for the distribution of client equity or debt securities, which includes a commitment to purchase such securities if they are not sold to third parties. Syndication and commitment fees include the arrangement and administration of a loan syndication, which includes a commitment to provide the loan if it is not sold to third parties. Total loans and advances at amortised cost Loans and receivables, category [member] Scenario weighting Scenario Probability Weighting The scenario probability weighting, expressed as a percentage and normalised to equate to 100%. The methodology works such that the baseline (reflecting current consensus outlook) has the highest weight and the weights of adverse and favourable scenarios depend on the deviation from the baseline; the further from the baseline, the smaller the weight. Barclays Bank PLC Subsidiary Barclays Bank PLC Subsidiary [Member] Barclays Bank PLC Subsidiary Debt securities in issue Debt securities in issue Debt instruments issued at amortised cost Loans and advances at amortised cost to customers Loans and advances to customers at amortised cost Loans Non-Asset-Backed Loans [Member] "This member stands for fixed rate loans, primarily the ESHLA portfolio, which are valued using models that discount expected future cash flows." Own credit Other comprehensive income, before tax, change in fair value of financial liability attributable to change in credit risk of liability Net transfers between stages Increase (decrease) through transfers, exposure to credit risk on loan commitments and financial guarantee contracts Reserves within equity [domain] Reserves within equity [domain] Barclays Bank PLC loans issued intra-group Barclays PLC Subordinated Liabilities, Loans Issued Intra-Group To Ultimate Parent [Member] This member stands for subordinated liabilities, loans issued intra-group by parent, Barclays Bank PLC to ultimate parent of group, Barclays PLC. Debt securities at amortised cost ECL movement on debt securities at amortised cost Debt securities [member] Additions, aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss Increase (decrease) through new transactions, aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss Net (losses)/gains from changes in fair value Gains (losses) on financial assets measured at fair value through other comprehensive income, before tax Total Gains (losses) recognised in profit or loss attributable to change in unrealised gains or losses for assets held at end of period, fair value measurement Segment consolidation items [axis] Segment consolidation items [axis] Retirement benefits Disclosure of employee benefits [text block] Characteristics of defined benefit plans [domain] Characteristics of defined benefit plans [domain] Investments in associates and joint ventures Investments accounted for using equity method Financial liabilities designated at fair value Financial liabilities at fair value through profit or loss, designated upon initial recognition or subsequently, category [member] Equity Equity [abstract] Disclosure of disaggregation of revenue from contracts with customers [table] Disclosure of disaggregation of revenue from contracts with customers [table] Fair value adjustments Accumulated Fair Value Hedge Adjustment On Hedged Item Included In Carrying Amount, Assets (Liabilities) The accumulated amount of fair value hedge adjustment on a hedged item that is included in the carrying amount of the hedged item, recognised in the statement of financial position as an asset or liability. Purchases, fair value measurement, liabilities Purchases, fair value measurement, liabilities Disclosure of operating segments [abstract] Disclosure of operating segments [abstract] Tax Income tax relating to cash flow hedges included in other comprehensive income UK regulatory levies UK Regulatory Levies UK Regulatory Levies Disclosure of transactions between related parties [abstract] Economic uncertainty adjustments Economic Uncertainty Adjustments [Member] Economic Uncertainty Adjustments Recoveries and reimbursements Increase (Decrease) Through Recoveries And Reimbursements, Financial Assets Increase (Decrease) Through Recoveries And Reimbursements, Financial Assets Classes of share capital [domain] Classes of share capital [domain] Loans and advances at amortised cost Increase (decrease) in financial assets [abstract] Assets classified as held for sale Assets and liabilities classified as held for sale [member] Analysis of movements in Level 3 assets and liabilities Disclosure Of Movements In Assets And Liabilities [Table Text Block] The tabular disclosure of the analysis of movements in assets and liabilities. Fair value through other comprehensive income reserve Other comprehensive income, net of tax, financial assets measured at fair value through other comprehensive income Classes of contingent liabilities [domain] Classes of contingent liabilities [domain] Financial assets at fair value through other comprehensive income Financial assets at fair value through other comprehensive income, category [member] Classes of financial liabilities [axis] Classes of financial liabilities [axis] Redemption of preference shares Decrease Through Redemption Of Preference Shares Decrease Through Redemption Of Preference Shares Classes of financial liabilities [domain] Classes of financial liabilities [domain] Net assets (liabilities) classified as held for sale Net Assets (Liabilities) Included in Disposal Groups Classified as Held For Sale Net Assets (Liabilities) Included in Disposal Groups Classified as Held For Sale Disclosure of other provisions [line items] Disclosure of other provisions [line items] Undrawn contractually committed facilities and guarantees Undrawn Contractually Committed Facilities And Guarantees [Member] This member stands for provisions are made if it is probable that a facility will be drawn and the resulting asset is expected to have a realisable value that is less than the amount advanced. Business activity in the year Increase through origination or purchase, exposure to credit risk on loan commitments and financial guarantee contracts Provisions Disclosure of other provisions [text block] Total gains or losses recognised in OCI, liabilities Gains (losses) recognised in other comprehensive income including exchange differences, fair value measurement, liabilities Brokerage and execution Brokerage Commissions And Client Execution Fees [Member] This member stands for fees earned for executing client transactions with exchanges and over-the- counter markets and assisting clients in clearing transactions. Called up share capital and share premium Called Up Share Capital And Share Premium The amount of issued capital including the amount received or receivable from issuance of the entity's shares in excess of nominal value. Barclays PLC Parent [member] Disclosure of management Value at Risk Management Value At Risk [Table Text Block] The tabular disclosure of the daily average, maximum and minimum values of management value at risk. Disclosure of management adjustment to models for impairment Explanation of credit risk management practices and how they relate to recognition and measurement of expected credit losses [text block] Redundancy and 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] ECL movement on loan commitments and other financial guarantees Off-Balance Sheet Loan Commitments And Financial Guarantee Contracts [Member] This member stands for off balance sheet loan commitments and financial guarantee contracts. Net assets classified as held for sale Net Assets (Liabilities) Or Disposal Groups Classified As Held For Sale Net Assets (Liabilities) Or Disposal Groups Classified As Held For Sale Number of lawsuits consolidated into a separate lawsuit Number Of Lawsuits Consolidated Into A Separate Lawsuit Number Of Lawsuits Consolidated Into A Separate Lawsuit Disclosure of contingent liabilities [abstract] Issuance costs of convertible instruments Issuance Costs Of Convertible Instruments Issuance Costs Of Convertible Instruments Total fees in scope of IFRS 15 revenues from contracts with customers Disclosure of disaggregation of revenue from contracts with customers [text block] Deposits at amortised cost from customers Deposits from customers at amortised cost Infrastructure, administration and general expenses Infrastructure, Administration And General Expenses Infrastructure, Administration And General Expenses Minimum Minimum [Member] Trading portfolio assets Financial assets at fair value through profit or loss, classified as held for trading, category [member] Purchases, fair value measurement, assets Purchases, fair value measurement, assets Non-interest income Other Income (Expense) Other Income (Expense) Barclays US Consumer Bank & Investment Bank Barclays US Consumer Bank & Investment Bank [Member] Barclays US Consumer Bank & Investment Bank Total liabilities Total liabilities Liabilities Financial assets at fair value through other comprehensive income Financial assets at fair value through other comprehensive income Civil actions in respect of the US anti-terrorism act - SDNY Civil Actions In Respect Of The US Anti-Terrorism Act - SDNY [Member] Civil Actions In Respect Of The US Anti-Terrorism Act - SDNY Subordinated liabilities Disclosure of subordinated liabilities [text block] Goodwill and intangible assets Disclosure of intangible assets and goodwill [text block] Vesting of Barclays PLC shares under share based payment schemes Increase (decrease) through exercise of options, equity Total gains and losses in the period recognised in the income statement, assets Gains (losses) recognised in profit or loss including exchange differences, fair value measurement, assets Financial liabilities at fair value through profit or loss, category other income Financial Liabilities At Fair Value Through Profit Or Loss, Category Other Income [Member] This member stands for the financial liabilities at fair value through profit or loss category, located in other income. [Refer: Financial liabilities at fair value through profit or loss] Tax Income tax relating to exchange differences on translation of foreign operations included in other comprehensive income Disclosure of credit risk exposure [abstract] Disclosure of credit risk exposure [abstract] Categories of financial assets [axis] Categories of financial assets [axis] Number of plaintiffs Number Of Plaintiffs Number Of Plaintiffs American Airlines Portfolio American Airlines Portfolio [Member] American Airlines Portfolio Disclosure of fair value of plan assets [line items] Disclosure of fair value of plan assets [line items] Products and services [axis] Products and services [axis] Disclosure of reserves within equity [line items] Disclosure of reserves within equity [line items] Disclosure of nature and extent of risks arising from financial instruments [table] Disclosure of nature and extent of risks arising from financial instruments [table] Disclosure of reserves within equity [abstract] Tax charge Tax expense (income) Commitments and Contingent Liabilities [Domain] Contingent Liabilities and Financial Guarantees [Domain] Contingent Liabilities and Financial Guarantees [Domain] Other reserves Disclosure Of Reserves Within Equity [Table Text Block] The tabular disclosure of other reserves within equity. Net investment expense Net Investment Income (Expense) The amount of income or expense arising from investments. Baseline Baseline [member] An external consensus forecast is assembled from key sources, including HM Treasury, Bloomberg and the Urban Land Institute. Financial guarantee contracts Financial guarantee contracts [member] Stage 1 12-month expected credit losses [member] Operating costs Operating Expenses Excluding Regulatory Levies, Litigation And Conduct Operating Expenses Excluding Regulatory Levies, Litigation And Conduct Legal, competition and regulatory matters Disclosure Of Legal, Competition And Regulatory Matters [Text Block] The disclosure of legal, competition and regulatory matters. Financial instruments at fair value, category Financial Instruments At Fair Value, Category [Member] This member stands for the financial instruments measured at fair value. Type of measurement of expected credit losses [domain] Type of measurement of expected credit losses [domain] Cash and balances at central banks Cash and bank balances at central banks Legal, Competition And Regulatory Matters Property, plant and equipment Property, plant and equipment including right-of-use assets Total liabilities Beginning balance, financial liabilities Ending balance, financial liabilities Financial liabilities, at fair value Document Period End Date Document Period End Date Non-adjusting events after reporting period [axis] Non-adjusting events after reporting period [axis] Assets included in disposal groups classified as held for sale Total assets classified as held for sale Non-current assets or disposal groups classified as held for sale Non-adjusting events after reporting period [domain] Non-adjusting events after reporting period [domain] Valuation techniques used in fair value measurement [domain] Valuation techniques used in fair value measurement [domain] Downside 1 Downside 1 [member] The downside 1 scenario. The adverse scenarios are calibrated to a similar severity to internal stress tests, whilst also considering IFRS 9 specific sensitivities and non-linearity. Maturity [axis] Maturity [axis] Coverage ratio Impairment Allowance Coverage Ratio The impairment allowances as a percentage of Credit Risk Loan balances. The impairment allowance is the aggregate of the identified and unidentified impairment (UI) balances. Settlements, fair value measurement, liabilities Settlements, fair value measurement, liabilities High Favourable changes Top of range [member] UK UNITED KINGDOM Other products Other Financial Instruments [Member] Other Financial Instruments Net drawdowns, repayments, net re-measurement and movement due to exposure and risk parameter changes Increase (decrease) through modification of contractual cash flows, financial assets Intangible assets and goodwill [abstract] Classes of financial instruments [axis] Classes of financial instruments [axis] ECL from assets classified as held for sale, adjustment ECL From Assets Classified As Held For Sale, Adjustment [Member] ECL From Assets Classified As Held For Sale, Adjustment Settlements, fair value measurement, assets Settlements, fair value measurement, assets Legal, competition and regulatory matters Legal proceedings provision [member] Reportable segments Reportable segments [member] Later than three years and not later than four years Later than three years and not later than four years [member] Customer redress Customer Redress [Member] This member stands for a provision for customer redress provisions comprise the estimated cost of making redress payments to customers, clients and counterparties for losses or damages associated with inappropriate judgement in the execution of our business activities. 5.200% Fixed Rate Resetting Subordinated Callable Notes (USD) 5.200% Fixed Rate Resetting Subordinated Callable Notes (USD) [Member] 5.200% Fixed Rate Resetting Subordinated Callable Notes (USD) Deposits at amortised cost Deposits at amortised cost Deposits at amortised cost Assets and liabilities held at fair value disaggregated by valuation technique (fair value hierarchy) and balance sheet classification and level 3 assets and liabilities held at fair value disaggregated by product type Disclosure Of Fair Value Measurement Of Assets And Liabilities [Table Text Block] The tabular disclosure of the fair value measurement of assets and liabilities disaggregated by valuation technique (fair value hierarchy) and balance sheet classification and product type. Retirement benefit remeasurements Other comprehensive income, net of tax, gains (losses) on remeasurements of defined benefit plans Document Type Document Type Fair value through other comprehensive income reserve Reserve of gains and losses on financial assets measured at fair value through other comprehensive income [member] Classes of financial assets [axis] Classes of financial assets [axis] Fee and commission expense Fee and commission expense Debt securities at amortised cost Debt instruments held at amortised cost Risk exposures [axis] Risk variables [axis] Other comprehensive income not recycled to profit or loss Other comprehensive income that will not be reclassified to profit or loss, net of tax Assets and liabilities classified as held for sale [axis] Assets and liabilities classified as held for sale [axis] Unrealised gains and losses recognised during the period on Level 3 assets and liabilities held at period end Disclosure Of Unrealised Gains (Losses) Recognised On Assets And Liabilities [Table Text Block] The tabular disclosure of unrealised gains and losses recognised during the period on assets and liabilities held at period end. Tax Income tax relating to components of other comprehensive income that will not be reclassified to profit or loss Profit or loss [abstract] Transfers Increase (decrease) through transfers, financial assets Statistical Measurement [Axis] Statistical Measurement [Axis] Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount [axis] Carrying amount, accumulated depreciation, amortisation and impairment and gross carrying amount [axis] Operating segments Operating segments [member] Modelled ECL Expected credit losses collectively assessed [member] Later than four years and not later than five years Later than four years and not later than five years [member] Loss contingency, damages sought, claimed amounts, value Loss Contingency, Damages Sought, Claimed Amounts, Value The monetary value of the award the plaintiff seeks in the legal matter, in addition to any interest, costs, and punitive damages. Borrowings by name [domain] Borrowings by name [domain] Proportion of Management adjustments to total impairment allowance Impairment Allowance Including Loan Commitments And Financial Guarantee Contracts Percentage Impairment Allowance Including Loan Commitments And Financial Guarantee Contracts Percentage Foreign exchange risk Currency risk [member] Number of convertible instruments redeemed Number Of Convertible Instruments Redeemed Number Of Convertible Instruments Redeemed Credit impairment charges Total income statement charges for the period Credit impairment (charges)/releases Impairment loss (reversal of impairment loss) recognised in profit or loss Net increase in debt securities in issue Adjustments for increase (decrease) in debt instruments issued Tax Income tax relating to financial assets measured at fair value through other comprehensive income included in other comprehensive income Total revenue from contracts with customers Revenue from contracts with customers Reconciliation of changes in fair value measurement, net assets (liabilities) [abstract] Reconciliation Of Changes In Fair Value Measurement, Net Assets (Liabilities) [Abstract] Reconciliation Of Changes In Fair Value Measurement, Net Assets (Liabilities) Range [axis] Range [axis] Components of equity [axis] Components of equity [axis] Other reserves Other Reserves And Other Shareholders Equity [Member] This member stands a component of equity representing reserves within equity, not including retained earnings. This does include the entity's own equity instruments, held by the entity or other members of the consolidated group. Fixed interest rate Fixed interest rate [member] 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] Subordinated liabilities [abstract] Deferred tax liabilities Deferred tax liabilities Profit/(loss) before tax Profit before tax Profit (loss) before tax Corporate income tax (paid)/received Income taxes paid (refund), classified as operating activities Other comprehensive income for the period Other comprehensive income Other comprehensive income Transfers out of Level 3 of fair value hierarchy, assets Transfers out of Level 3 of fair value hierarchy, assets Transfers out of Level 3 of fair value hierarchy, assets Investment property Investment property Past due status [domain] Past due status [domain] Net (increase)/decrease in loans and advances at amortised cost Adjustments for decrease (increase) in loans and advances Final repayments Decrease Through Final Repayments, Financial Assets The decrease in financial assets resulting from final repayments. [Refer: Financial assets] Categories of related parties [domain] Categories of related parties [domain] Disclosure of other provisions [table] Disclosure of other provisions [table] Assets and liabilities [axis] Assets and liabilities [axis] Retirement benefit assets Net defined benefit asset Classes of financial instruments [domain] Classes of financial instruments [domain] Dividends [Abstract] Dividends [Abstract] Increase (decrease) in exposure to credit risk on loan commitments and financial guarantee contracts [abstract] Increase (decrease) in exposure to credit risk on loan commitments and financial guarantee contracts [abstract] Number of banks claims against Number of Banks Claims Against Number of Banks Claims Against ECL from other financial assets subject to impairment, adjustment ECL From Other Financial Assets Subject To Impairment, Adjustment [Member] ECL From Other Financial Assets Subject To Impairment, Adjustment Products and services [domain] Products and services [domain] Analysis of results by business Disclosure of operating segments [text block] Transfers from Stage 1 to Stage 2 Transfers From Stage One To Stage Two [Member] This member stands for transfers from Stage one. Other financial assets subject to impairment ECL movement on other financial assets Other Financial Assets Subject To Impairment [Member] This member stands for other financial assets subject to impairment, which includes cash collateral and settlement balances, financial assets at fair value through other comprehensive income, accrued income and sundry debtors. Contingent liabilities and commitments Disclosure Of Contingent Liabilities And Commitments [Table Text Block] Disclosure Of Contingent Liabilities And Commitments HM Revenue and Customs (HMRC) assessments concerning UK Value Added Tax [member] HM Revenue and Customs (HMRC) assessments concerning UK Value Added Tax [member] In March 2018 HMRC issued notices that have the effect of removing certain overseas subsidiaries that have operations in the UK from Barclays UK VAT group, in which group supplies between members are generally free from VAT. Sundry provisions Miscellaneous other provisions [member] Borrowings by name [axis] Borrowings by name [axis] Derivative credit valuation adjustments Derivative Credit Valuation Adjustments [Member] This member stands for derivative credit valuation adjustment for the impact on fair value of counterparty credit risk. Other adjustments Other Adjustments [Member] Other Adjustments Government and Government sponsored debt Government And Government Sponsored Debt [Member] Government And Government Sponsored Debt Net drawdowns, repayments, net re-measurement and movement due to exposure and risk parameter changes Increase (Decrease) In Drawdowns, Repayments, Risk Parameter Changes And Other Movements, Exposure To Credit Risk On Loan Commitments And Financial Guarantee Contracts Increase (Decrease) In Drawdowns, Repayments, Risk Parameter Changes And Other Movements, Exposure To Credit Risk On Loan Commitments And Financial Guarantee Contracts Financial liabilities at fair value through profit or loss, category trading Financial Liabilities At Fair Value Through Profit Or Loss, Category Trading [Member] This member stands for the financial liabilities at fair value through profit or loss category, located in trading income. [Refer: Financial liabilities at fair value through profit or loss] Settlements, fair value measurement, assets (liabilities), net Settlements, Fair Value Measurement, Assets (Liabilities), Net The decrease in the fair value measurement of assets and liabilities resulting from settlements of those assets and liabilities. [Refer: At fair value [member]] Disclosure of detailed information about intangible assets [table] Disclosure of detailed information about intangible assets [table] Other reserves Other reserves Impairment allowance Accumulated impairment [member] Contingent liabilities and commitments Disclosure of commitments and contingent liabilities [text block] Other reserves Disclosure of reserves within equity [text block] Defined benefit plans [domain] Defined benefit plans [domain] Country of domicile Country of domicile [member] Interest rate Borrowings, interest rate Net cash from investing activities Cash flows from (used in) investing activities Net increase in cash and cash equivalents Increase (decrease) in cash and cash equivalents after effect of exchange rate changes Refinements to models used for calculation Increase (decrease) through changes in models or risk parameters, financial assets Credit risk Disclosure of objectives, policies and processes for managing capital [text block] ECL charge on assets held for sale Increase (Decrease) Through Assets Held For Sale Movements, Financial Assets Increase (Decrease) Through Assets Held For Sale Movements, Financial Assets Subordinated liabilities Subordinated liabilities Opening balance as at 1 January Closing balance Subordinated liabilities Compensatory interest Provisions, Annual Compensatory Interest Provisions, Annual Compensatory Interest Number of convertible instruments issued Number Of Convertible Instruments Issued Number Of Convertible Instruments Issued Disclosure of detailed information about intangible assets [line items] Disclosure of detailed information about intangible assets [line items] Favorable changes, Income Statement Increase In Fair Value Measurement Due To Change In Multiple Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Recognised In Profit Or Loss, After Tax, Assets (Liabilities) The amount of increase in the fair value measurement of assets (liabilities), recognised in profit or loss after tax, due to a change in multiple unobservable inputs to reflect reasonably possible alternative assumptions. [Refer: Tax income (expense)] Bank rate Bank Rate [member] This member stands for bank rate. Net cash from financing activities Cash flows from (used in) financing activities Staff costs Employee benefits expense Barclays UK PLC Barclays UK PLC [member] This member stands for the disposal of the Barclays UK business, a discontinued operation. The division of Barclays which was ring-fenced as part of regulatory ring fencing requirements. The division includes the UK Personal business; the small UK Corporate and UK Wealth businesses; and the Barclaycard UK consumer credit cards business. This group of assets, which are to be disposed of together as a group in a single transaction, and the liabilities directly associated with those assets that will be transferred in the transaction. Called up share capital and share premium Issued Capital And Share Premium [Member] This member stands for the issued capital including the amount received or receivable from issuance of the entity shares in excess of nominal value. Spread risk Spread Risk [Member] This member stands for the spread risk factor. Lifetime expected credit losses Lifetime expected credit losses [member] Business activity in the period Increase through origination or purchase, financial assets Consolidated Entities [Domain] Consolidated Entities [Domain] Disclosure of operating segments [table] Disclosure of operating segments [table] Statement of changes in equity [table] Statement of changes in equity [table] Total gains and losses in the period recognised in the income statement, liabilities Gains (losses) recognised in profit or loss including exchange differences, fair value measurement, liabilities Equity risk Equity derivatives Equity price risk [member] Segments [axis] Segments [axis] Types of risks [axis] Types of risks [axis] Transfers from Stage 3 Transfers From Stage Three [Member] This member stands for transfers from Stage three. Current Fiscal Year End Date Current Fiscal Year End Date Fair value adjustments Disclosure Of Fair Value Adjustments [Table Text Block] The tabular disclosure of key balance sheet valuation adjustments. Number of lawsuits with damages sought Number Of Lawsuits With Specified Damages Sought The number of lawsuits with damages sought specified. Own credit Other comprehensive income, net of tax, change in fair value of financial liability attributable to change in credit risk of liability Low Bottom of range [member] Stage 3 Financial instruments credit-impaired [member] Categories of related parties [axis] Categories of related parties [axis] Disclosure of detailed information about borrowings [line items] Disclosure of detailed information about borrowings [line items] Disclosure of non-adjusting events after reporting period [table] Disclosure of non-adjusting events after reporting period [table] Non-modelled exposures ECL From Non-Modelled Exposures [Member] ECL from non-modelled exposures Profit after tax Profit after tax Profit (loss) Cash flow hedges Other comprehensive income, net of tax, cash flow hedges Post write-off recoveries Gain on recovery of loans and advances previously written off Financial assets Opening balance Ending balance Financial assets Financial assets Financial assets Financial assets Barclays Bank PLC Barclays Bank PLC [member] This member stands for the Barclays Bank PLC, the immediate parent company of Barclays Group PLC. Amendment Flag Amendment Flag Components of equity [domain] Components of equity [domain] Uncollateralised derivative funding Uncollateralised Derivative Funding [Member] Total Dividends recognised as distributions to owners Disclosure of operating segments [line items] Disclosure of operating segments [line items] Fair value through other comprehensive income reserve Financial assets measured at fair value through other comprehensive income [abstract] Federal funds rate Federal Funds Rate [Member] This member stands for Federal funds rate. Average Weighted average [member] Expected credit losses held against contingent liabilities and commitments Provision for credit commitments [member] Segmental reporting Disclosure of entity's operating segments [text block] Current tax assets Current tax assets Risk variables [domain] Risk variables [domain] Method of assessment of expected credit losses [domain] Method of assessment of expected credit losses [domain] Number of lawsuits dismissed Number Of Lawsuits Dismissed Number Of Lawsuits Dismissed Range [domain] Range [domain] Total impairment allowance Impairment Allowance, Total [Member] Impairment Allowance, Total Classes of contingent liabilities [axis] Classes of contingent liabilities [axis] Disclosure of macroeconomic variables Disclosure Of Analysis Of Credit Exposures Using An External Credit Grading System [Text Block] Disclosure Of Analysis Of Credit Exposures Using An External Credit Grading System Retained earnings Retained earnings [member] Post-model adjustment Post-Model Adjustment [Member] Post-Model Adjustment Later than one year and not later than two years Later than one year and not later than two years [member] Recurring fair value measurement Recurring fair value measurement [member] Disclosure of contingent liabilities [table] Disclosure of contingent liabilities [table] Assets and liabilities not classified as held for sale Assets and liabilities not classified as held for sale [member] Loans and advances at amortised cost to banks Loans and advances to banks at amortised cost Financial assets at fair value through profit or loss, category other income Financial Assets At Fair Value Through Profit Or Loss, Category Other Income [Member] This member stands for the financial assets at fair value through profit or loss category, located in other income. [Refer: Financial liabilities at fair value through profit or loss] Gain on exit of American Airlines partnership Gain (Loss) From Disposal of Non-Current Assets or Disposal Groups Classified as Held For Sale and Discontinued Operations Gain (Loss) From Disposal of Non-Current Assets or Disposal Groups Classified as Held For Sale and Discontinued Operations Unfavorable changes, Income Statement Decrease In Fair Value Measurement Due To Change In Multiple Unobservable Inputs To Reflect Reasonably Possible Alternative Assumptions, Recognised In Profit Or Loss, After Tax, Assets (Liabilities) The amount of decrease in the fair value measurement of assets (liabilities), recognised in profit or loss after tax, due to a change in multiple unobservable inputs to reflect reasonably possible alternative assumptions. [Refer: Tax income (expense)] Liabilities Liabilities [abstract] Transfers out of Level 3 of fair value hierarchy, assets (liabilities), net Transfers Out Of Level 3 Of Fair Value Hierarchy, Assets (Liabilities), Net The amount of transfers of assets less liabilities out of Level 3 of the fair value hierarchy. [Refer: Level 3 of fair value hierarchy [member]] Consolidated Entities [Axis] Consolidated Entities [Axis] Specific bases Specific Bases [Member] This member stands for macroeconomic variables used in the calculation of ECL based on specific bases. Net assets (liabilities) at fair value through profit or loss, category trading income Net Assets (Liabilities) At Fair Value Through Profit Or Loss, Category Trading Income [Member] This member stands for the net assets (liabilities) at fair value through profit or loss category, located in trading income. [Refer: Financial liabilities at fair value through profit or loss] Categories of financial assets [domain] Categories of financial assets [domain] Retail other Other, Retail [Member] Other, Retail Provisions [abstract] Other Other Fees [Member] This member stands for other fees, not separately disclosed. Others fees includes the intercompany balances earned from different group entities. Carrying amount Carrying amount [member] Dividends on ordinary shares and preference shares Disclosure of dividends [text block] Total loans and advances at amortised cost including debt securities Loans And Advances At Amortised Cost, Including Debt Securities [Member] Loans And Advances At Amortised Cost, Including Debt Securities Barclays UK Corporate Bank Barclays UK Corporate Bank [Member] Barclays UK Corporate Bank Notional amount Notional amount Net release of impairment Reclassification Adjustments On Financial Assets Measured At Fair Value Through Other Comprehensive Income, Before Tax, Due To Impairment The amount of reclassification adjustments due to impairment of financial assets measured at fair value through other comprehensive income, before tax. Reclassification adjustments are amounts reclassified to profit (loss) in the current period that were recognised in other comprehensive income in the current or previous periods. [Refer: Financial assets measured at fair value through other comprehensive income; Other comprehensive income] Civil actions in respect of the US anti-terrorism act - EDNY Civil Actions In Respect Of The US Anti-Terrorism Act - EDNY [Member] Civil complaints against Barclays Bank PLC and other banks allege engagement in a conspiracy and violation of the US Anti-Terrorism Act (ATA). Dividends on ordinary shares and preference shares Dividends On Ordinary Shares And Preference Shares [Table Text Block] The tabular disclosure of detailed information of dividends on ordinary shares. Cash flow hedging reserve Reserve of cash flow hedges [member] Fee and commission income (expense) [abstract] Litigation settlements approved, value Litigation Settlements Approved, Value The amount of litigation settlements approved or agreed upon. Other equity instruments coupons paid Coupons Paid On Other Equity Instruments The amount of increase (decrease) in equity through other equity instruments coupons paid. Downside 2 Downside 2 [member] The downside 2 scenario. The adverse scenarios are calibrated to a similar severity to internal stress tests, whilst also considering IFRS 9 specific sensitivities and non-linearity. Downside 2 is benchmarked to the Bank of England's annual cyclical scenarios and to the most severe scenario from Moody's inventory, but is not designed to be the same. The Downside 2 scenario represents a severe global recession with substantial falls in both UK and US GDP. Unemployment in both markets rises towards 9% and there are substantial falls in asset prices including housing. Stage 2 Financial instruments not credit-impaired [member] Currency translation reserve Exchange differences on translation [abstract] Amortisation and releases, aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss Increase (decrease) through amounts recognised in profit or loss, aggregate difference between fair value at initial recognition and transaction price yet to be recognised in profit or loss Other non-contract fee income Other fee and commission income Maturity [domain] Maturity [domain] Surplus (deficit) in plan Surplus (deficit) in plan Total gains or losses recognised in OCI, assets (liabilities), net Gains (Losses) Recognised In Other Comprehensive Income Including Exchange Differences, Fair Value Measurement, Assets (Liabilities) The gains (losses) including exchange differences recognised in other comprehensive income on the fair value measurement of assets net of liabilities. [Refer: At fair value [member]; Other comprehensive income] Categories of financial liabilities [axis] Categories of financial liabilities [axis] Net increase in deposits at amortised cost Adjustments for increase (decrease) in deposits Barclays Investment Bank Barclays Investment Bank [Member] Barclays Investment Bank Credit impairment of financial instruments [domain] Credit impairment of financial instruments [domain] 6.174% Fixed Rate Resetting Subordinated Callable Notes (GBP) 6.174% Fixed Rate Resetting Subordinated Callable Notes (GBP) [Member] 6.174% Fixed Rate Resetting Subordinated Callable Notes (GBP) At fair value At fair value [member] Beginning balance, assets (liabilities), net Ending balance, assets (liabilities), net Assets (liabilities) >30 days past due Greater Than One Month Past Due [Member] This member stands for a time band of later than one month. Upside 2 Upside 2 [member] The upside 2 scenario. The favourable scenarios are calibrated to be symmetric to the adverse scenarios, subject to a ceiling calibrated to relevant recent favourable benchmark scenarios. Financial liabilities Categories of financial liabilities [abstract] Transfers from Stage 2 to Stage 1 Transfers From Stage Two To Stage One [Member] This member stands for Transfers from stage two. Retirement benefit liabilities Net defined benefit liability Disclosure of fair value of plan assets [table] Disclosure of fair value of plan assets [table] Assets By Functions [Domain] Assets By Functions [Domain] Assets By Functions [Domain] Net losses/(gains) transferred to net profit Reclassification adjustments on cash flow hedges, before tax Brokered certificates of deposit Brokered Certificates Of Deposit [Member] This member stands for structured and brokered certificates of deposit issued by the entity are insured up to $250,000 per depositor by the Federal Deposit Insurance Corporation (FDIC) in the US.