Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Commodity contracts Commodity Contract [Member] Default rate Measurement Input, Default Rate [Member] Cash Collateral Received Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash, Offset Against Derivative Asset Award Timing Predetermined Award Timing Predetermined [Flag] Indefinite-Lived Intangible Assets [Axis] Indefinite-Lived Intangible Assets [Axis] Amortization method qualified affordable housing investments, amortization Investment Program, Proportional Amortization Method, Applied, Amortization Expense Entity File Number Entity File Number Discover Discover [Member] Discover Additional Paid-In Capital Additional Paid-in Capital [Member] Tabular List, Table Tabular List [Table Text Block] Charge-offs Amounts due from partners for charged off loans Financing Receivable, Allowance for Credit Loss, Writeoff Schedule of Fair Value of Financial Instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Measurement input, yield Measurement Input, Yield [Member] Measurement input using interest rate correlation Award Share-Based Payment Arrangement [Member] Carrying Amount Liabilities Carrying Amount Of Liabilities The carry amount of liabilities in fair value hedging relationship Goodwill [Line Items] Goodwill [Line Items] Amortized cost basis of investment securities available for sale Available-for-sale Securities, Expected Debt Maturities, Amortized Cost Basis, Rolling Maturity Available-for-sale Securities, Expected Debt Maturities, Amortized Cost Basis, Rolling Maturity Measurement Basis [Axis] Measurement Basis [Axis] Adjustment to Compensation: Adjustment to Compensation [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Financing Receivable Portfolio Segment [Domain] Financing Receivable Portfolio Segment [Domain] Dividends paid Payments of Ordinary Dividends, Preferred Stock and Preference Stock Schedule of Stock by Class [Table] Stock, Class of Stock [Table] Fair value of investment securities available for sale: Available-for-sale Securities, Expected Debt Maturities, Fair Value, Rolling Maturity [Abstract] Available-for-sale Securities, Expected Debt Maturities, Fair Value, Rolling Maturity [Abstract] Due > 10 Years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost Non-Recoverable Rate Non-Recoverable Rate [Member] Non-Recoverable Rate [Member] Cash Collateral Pledged Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Offset Adjustment to Compensation, Amount Adjustment to Compensation Amount Percentage of portfolio Concentration Risk, Percentage Changes in other assets Increase (Decrease) in Other Operating Assets Stock-based compensation expense Share-Based Payment Arrangement, Noncash Expense Stock options Share-Based Payment Arrangement, Option [Member] Net loans held for investment Net loans held for investment Financing Receivable, after Allowance for Credit Loss Net unrealized gains (losses) included in OCI related to assets and liabilities still held Fair Value, Assets Measure on Recurring Basis, Unrealized Gain (Loss) in OCI Amount of unrealized gain (loss) which is included in other comprehensive income related to those assets still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3) Balance Sheet Offsetting of Financial Assets and Liabilities Derivatives, Offsetting Fair Value Amounts, Policy [Policy Text Block] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Net unrealized gains (losses) on hedging relationships Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Total stockholders’ equity Beginning balance Ending balance Equity, Attributable to Parent Measurement Frequency [Axis] Measurement Frequency [Axis] Debt Securities, Available-for-Sale [Table] Debt Securities, Available-for-Sale [Table] Insider Trading Policies and Procedures [Line Items] Other non-interest income Other Non-Interest Income [Member] Other Non-Interest Income [Member] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Financial assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Recurring Fair Value, Recurring [Member] Cover [Abstract] Cover [Abstract] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Maximum Maximum Maximum [Member] Investment securities held to maturity Total Amortized Cost Basis Debt Securities, Held-to-Maturity, Excluding Accrued Interest, before Allowance for Credit Loss Other intangible assets (definite lived): Total estimated future amounts Finite-Lived Intangible Assets, Net Fair Value - Total Debt Securities, Available-for-Sale, Unrealized Loss Position VIE, nonconsolidated, carrying amount of assets included in certain investment structures Variable Interest Entities, nonconsolidated, Carrying amount of Assets included in certain investment structures In certain investment structures, we consolidate a VIE which in turn holds as its primary asset an investment in an unconsolidated VIE. This concept represents the carrying amount of assets related to these investment structures. Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Debt Instrument [Line Items] Debt Instrument [Line Items] Preferred stock, dividend rate, basis spread on variable rate Preferred Stock, Dividend Rate, Basis Spread On Variable Rate Preferred Stock, Dividend Rate, Basis Spread On Variable Rate Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Financing Receivable, Credit Quality Indicator [Table] Financing Receivable, Credit Quality Indicator [Table] Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Due > 10 Years Debt Securities, Held-to-Maturity, Weighted Average Yield, Maturity, after Year 10 Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Payment delay duration (in months) Financing Receivable, Modified, Weighted Average Term Increase from Modification Income from continuing operations before income taxes Income (loss) from continuing operations before income taxes Income (loss) from continuing operations before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Entity Shell Company Entity Shell Company Revolving Loans Converted to Term Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Schedule of Intangible Assets by Major Class [Table] Schedule of Intangible Assets by Major Class [Table] Schedule of Intangible Assets by Major Class [Table] Schedule of Letter of Credit and Other Loan Commitments Schedule of Letter of Credit and Other Loan Commitments [Table Text Block] Schedule of Letter of credit and other loan commitments Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Discontinued Hedging Relationships, Liabilities Hedged Liability, Discontinued Fair Value Hedge, Cumulative Increase (Decrease) Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Depositary Shares, Each Representing a 1/40th Interest in a Share of Fixed Rate Non-Cumulative Perpetual Preferred Stock, Series I Series I Series I Preferred Stock [Member] Outstanding nonredeemable series I preferred stock or outstanding series I preferred stock. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer. Operating segments Operating Segments [Member] Securitized Debt Obligations Interest expense - Securitized Debt Obligation [Member] Interest expense - Securitized Debt Obligation [Member] Net unrealized gains (losses) on hedging relationships Net unrealized gains (losses) on hedging relationships Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Short-term borrowings: Short-Term Debt [Abstract] Total interest expense Interest Expense, Operating Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] RMBS, Agency Residential Mortgage Backed Securities, Agency [Member] Securities collateralized by agency residential real estate mortgage loans. Income (loss) from continuing operations, net of tax Income (loss) from continuing operations, net of tax Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Letter of credit Letter of Credit [Member] % of total class of receivables Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage Maximum length of time over which forecasted transactions were hedged, years Maximum Length of Time Hedged in Cash Flow Hedge Dividends and undistributed earnings allocated to participating securities Participating Securities, Distributed and Undistributed Earnings (Loss), excluding Preferred Stock Dividends, Basic Participating Securities, Distributed and Undistributed Earnings (Loss), excluding Preferred Stock Dividends, Basic Document Fiscal Period Focus Document Fiscal Period Focus Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax, Portion Attributable to Parent Net Carrying Amount Intangible Assets, Net (Including Goodwill) Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Award Timing Method Award Timing Method [Text Block] Litigation Case Litigation Case [Domain] Net income (loss) from continuing operations (in dollars per share) Income (Loss) from Continuing Operations, Per Basic Share Award Type Award Type [Axis] Foreign Currency Translation Adjustments Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Hedging Relationship [Domain] Hedging Relationship [Domain] Unsecuritized loans held for investment Parent Company [Member] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Collaborative Arrangement and Arrangement Other than Collaborative [Line Items] Trading Symbol Trading Symbol Accumulated Amortization Servicing Asset at Amortized Cost, Accumulated Amortization Servicing Asset at Amortized Cost, Accumulated Amortization Components of Goodwill, Intangible Assets and MSRs Schedule of Intangible Assets and Goodwill [Table Text Block] Entity Address, City or Town Entity Address, City or Town Short-term Debt, Type [Domain] Short-Term Debt, Type [Domain] Preferred stock: Proceeds from Issuance or Sale of Equity [Abstract] Class of Financing Receivable [Axis] Class of Financing Receivable [Axis] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Income Statement Location [Domain] Statement of Income Location, Balance [Domain] Time deposits, at or above FDIC insurance limit Time Deposits, at or Above FDIC Insurance Limit Allowance for Credit Losses - Investment Securities Credit Loss, Financial Instrument [Policy Text Block] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Business combination, consideration transferred Business Combination, Consideration Transferred Commercial and industrial Commercial And Industrial [Member] Commercial and industrial. Entity Emerging Growth Company Entity Emerging Growth Company Derivative, collateral, right to reclaim cash Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Not Offset Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Reserve for unfunded lending commitments Unfunded Loan Commitment [Member] Restricted cash for securitization investors Restricted Cash and Cash Equivalent Other intangible assets (indefinite lived): Indefinite-Lived Intangible Assets (Excluding Goodwill) Total non-interest income Non-interest income (loss) Noninterest Income Other contingently issuable shares (in shares) Incremental Common Shares Attributable to Dilutive Effect of Contingently Issuable Shares Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Gross Unrealized Losses Debt Securities, Held-to-Maturity, Accumulated Unrecognized Loss Other Other assets Other Assets, Fair Value Disclosure Non-interest expense: Noninterest Expense [Abstract] Auto loan securitizations Collateralized Auto Loans [Member] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Cash and due from banks Cash and Due from Banks Affordable housing tax credits Investment Program, Proportional Amortization Method, Elected, Income Tax Credit and Other Income Tax Benefit, before Amortization Expense Class of Financing Receivable [Domain] Class of Financing Receivable [Domain] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] Guarantee obligation Guarantor Obligations, Current Carrying Value Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] International card businesses: Geographic Distribution, Foreign [Member] Derivative, Fair Value, Net [Abstract] Derivative, Fair Value, Net [Abstract] Due > 1 Year through 5 Years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five Weighted-average interest rate reduction Financing Receivable, Modified, Weighted Average Interest Rate Decrease from Modification Entity Address, Postal Zip Code Entity Address, Postal Zip Code Restatement Determination Date Restatement Determination Date Other Other Other Comprehensive Income Other, Net Of Tax, Attributable To Parent Other Comprehensive Income Other, Net Of Tax, Attributable To Parent Investment securities Investment Securities Interest and Dividend Income, Securities, Operating Income tax provision Income tax provision (benefit) Income Tax Expense (Benefit) Investment securities held to maturity: Payments to Acquire Investments [Abstract] Net loss from discontinued operations (in dollars per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Other assets Other Assets Exercises of stock options Stock Issued During Period, Value, Stock Options And Warrants Exercised And Restricted Stock Vesting Stock Issued During Period, Value, Stock Options And Warrants Exercised And Restricted Stock Vesting Beginning balance Ending balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Senior and subordinated notes Unsecured debt Unsecured Debt Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] Derivatives designated as accounting hedges: Designated as Hedging Instrument [Member] Deposit liability, uninsured Deposit Liability, Uninsured Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Hedging Relationship [Axis] Hedging Relationship [Axis] Due in 1 Year or Less Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, Year One Other Other Contract Revenue [Member] Other contract revenue [Member] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Business Combinations Mergers, Acquisitions and Dispositions Disclosures [Text Block] Net cash used in other investing activities Payments to Acquire Businesses, Net of Cash Acquired All Trading Arrangements All Trading Arrangements [Member] Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Preferred stock dividends Preferred Stock Dividends, Income Statement Impact Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Investment securities Security Owned and Pledged as Collateral, Associated Liabilities, Fair Value Net cash from operating activities Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Proceeds from sales Proceeds from Sale of Debt Securities, Available-for-Sale Investment securities available for sale (amortized cost basis of $97.5 billion and $97.7 billion and allowance for credit losses of $3 million as of both March 31, 2026 and December 31, 2025) Fair Value Total Debt Securities, Available-for-Sale, Excluding Accrued Interest Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Subsequent Event Subsequent Event [Member] Recoveries Financing Receivable, Allowance for Credit Loss, Recovery Net interest income Interest Income (Loss) Net interest income Interest Income (Expense), Operating Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] PEO Total Compensation Amount PEO Total Compensation Amount Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Estimated future amounts for the period between April 1, 2026 and December 31, 2026 Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year Equity Components [Axis] Equity Components [Axis] Term Loans by Vintage Year, Year 4 Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Number of portfolio segments Number of Reportable Segments Commercial MSRs Servicing Asset [Abstract] Variable Interest Entities and Securitizations Variable Interest Entity Disclosure [Text Block] Percentage, Nonperforming Loans Financing Receivable, Nonaccrual, Percent Past Due Entity Address, State or Province Entity Address, State or Province Total interest income Interest and Dividend Income, Operating Financial Asset, Period Past Due [Domain] Financial Asset, Aging [Domain] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Security, Excluded EPS Calculation [Table] Commercial and multifamily real estate Commercial And Multifamily Real Estate [Member] Property that is used for business purposes or multifamily residential. Dividends—common stock Dividends, Common Stock Euro Euro Member Countries, Euro Loans held for investment Net loans held for investment Loans Receivable, Fair Value Disclosure Before Tax Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent [Abstract] Individual: Individual [Axis] Dividends paid Payments of Ordinary Dividends, Common Stock Entities [Table] Entities [Table] Total other debt Debt, Excluding Secured Debt Debt, Excluding Secured Debt Net Carrying Amount Servicing Asset at Amortized Cost Maximum Exposure to Loss VIE, reporting entity involvement, maximum loss exposure Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Professional services Professional and Contract Services Expense Principal balance reduction Principal Forgiveness [Member] Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Entity Interactive Data Current Entity Interactive Data Current Loss Contingency, Nature Loss Contingency, Nature [Domain] Matthew W. Cooper [Member] Matthew W. Cooper Financing Receivable, Troubled Debt Restructuring [Line Items] Financing Receivable, Modified [Line Items] Interest income: Interest and Dividend Income, Operating [Abstract] Total non-interest expense Non-interest expense Noninterest Expense Due > 1 Year through 5 Years Debt Securities, Held-to-Maturity, Weighted Average Yield, Maturity, after Year One Through Five Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Allowance for Credit Losses and Reserve for Unfunded Lending Commitments Allowance for Credit Losses [Text Block] Deposits Interest-bearing Deposits Interest Expense, Deposits Non-interest income: Noninterest Income [Abstract] Special assessment fees Special Assessment Fees Special Assessment Fees Appraisal value Appraisal Value [Member] Appraisal value. Entity Central Index Key Entity Central Index Key PEO Name PEO Name Total net revenue (loss) Revenues Gains (losses) recognized in other non-interest income: Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Credit Quality Indicator Financing Receivable Credit Quality Indicators [Table Text Block] Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Carrying Value (in millions) Preferred Stock, Including Additional Paid in Capital, Net of Discount Qualified affordable housing investments, commitment Investment Program, Proportional Amortization Method, Elected, Commitment Non-interest-bearing deposits Noninterest-Bearing Deposit Liabilities Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Derivative Asset, netting adjustments Derivative Asset, Subject to Master Netting Arrangement, Gross Liability and Collateral, Obligation to Return Cash, Offset Amortized cost basis of investment securities held to maturity: Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value, Rolling Maturity [Abstract] Schedule of Derivative Assets and Liabilities at Fair Value Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Exercise Price Award Exercise Price Entity Filer Category Entity Filer Category Class of Stock [Domain] Class of Stock [Domain] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Total Assets Hedged asset, fair value hedge, cumulative increase (decrease) Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease) Balance Sheet Location [Axis] Statement of Financial Position Location, Balance [Axis] 2029 Finite-Lived Intangible Asset, Expected Amortization, Year Three Loans held for investment Financing Receivable, before Allowance for Credit Loss Entities that provide capital to low-income and rural communities Investment Companies Providing Capital to Low-Income and Rural Communities [Member] Investment Companies Providing Capital to Low-Income and Rural Communities Customer net revenue range Customer Net Revenue Range Customer Net Revenue Range Other intangible assets (definite lived): Finite-Lived Intangible Assets, Gross Deposits and Borrowings Debt and Deposit Liabilities Disclosures [Text Block] Information about short-term and long-term debt arrangements, including amounts of borrowings, repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements. Also includes the entire disclosure for deposit liabilities including data and tables. Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Savings Account and Related Attorney General Litigation Savings Account and Related Attorney General Litigation [Member] Savings Account and Related Attorney General Litigation Other debt: Other Debt [Abstract] Other debt. Entity Address, Address Line One Entity Address, Address Line One Accumulated Other Comprehensive Loss Total AOCI Attributable to Parent [Member] Investments [Domain] Investments [Domain] Measurement input, swap rates Measurement Input, Swap Rates [Member] Measurement input using swap rates Revolving Loans Converted to Term Financing Receivable, Excluding Accrued Interest, Revolving, Converted to Term Loan, Writeoff Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract] Total liabilities Fair Value Hedge Liabilities Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Derivative Instruments and Hedging Activities Derivative Instruments and Hedging Activities Disclosure [Text Block] Fair Value Debt Securities, Held-to-Maturity, Excluding Accrued Interest, Nonaccrual Schedule of Preferred Stock Schedule of Stock by Class [Table Text Block] Fair Value as of Grant Date Award Grant Date Fair Value Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax, Portion Attributable to Parent Term Loans by Vintage Year, Year 5 Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year Financing Receivable, Modified, Subsequent Default [Line Items] Financing Receivable, Modified, Subsequent Default [Line Items] Salaries and associate benefits Labor and Related Expense Stock options (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Personal loans—Delinquency status: Personal Loans Portfolio Segment [Member] Personal Loans Portfolio Segment Customer accommodation: Customer Accommodation [Member] Customer accommodation derivative contracts Document Quarterly Report Document Quarterly Report Fair Value - Less than 12 Months Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis Quantitative Information Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Financial Instrument Performance Status [Axis] Financial Instrument Performance Status [Axis] Counterparty Name [Domain] Counterparty Name [Domain] 90 Plus Day Delinquent Loans Accruing Interest and Nonperforming Loans Financing Receivable, Nonaccrual [Table Text Block] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Loans held for investment: Loans and Leases Receivable, Net Amount [Abstract] Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Net unrealized gains (losses) on securities available for sale Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, before Tax, Portion Attributable to Parent Net unrealized gains (losses) on securities available for sale Other Comprehensive Income (Loss), Available-for-Sale Securities, Tax, Portion Attributable to Parent Investment Type [Axis] Investment Type [Axis] Title Trading Arrangement, Individual Title Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Series O Series O Preferred Stock [Member] Series O Preferred Stock Securities Collateral Held Under Master Netting Agreements Derivative Asset, Fair Value of Collateral Total cash consideration for acquisition Payments to Acquire Businesses, Gross Non-PEO NEO Non-PEO NEO [Member] Per Annum Dividend Rate Preferred Stock, Dividend Rate, Percentage Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Other Other Other Intangible Assets [Member] Gross Unrealized Gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Offsetting Assets Offsetting Assets [Table Text Block] All Award Types Award Type [Domain] Fair Value Inputs Level 1 And Level 2 Fair Value Inputs Level 1 And Level 2 [Member] Fair Value Inputs Level 1 And Level 2 Net unrealized gains (losses) on hedging relationships Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax Federal Home Loan banks Federal Home Loan banks [Member] Federal Home Loan banks [Member] Equity Awards Adjustments Equity Awards Adjustments [Member] Other, net Other Noncash Income (Expense) Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Compensation Amount Outstanding Recovery Compensation Amount Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Foreign exchange and other contracts Foreign Exchange Contract [Member] Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Estimated Fair Value Estimate of Fair Value Measurement [Member] Sanjiv Yajnik [Member] Sanjiv Yajnik Criticized performing Performing Financial Instruments [Member] MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] Components of Other Comprehensive Income (Loss) and Related Tax Impact Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Financing Receivable, Past Due [Line Items] Financing Receivable, Past Due [Line Items] Total long-term debt Long-Term Debt and Lease Obligation Amortization method qualified affordable housing investments Investment, Proportional Amortization Method, Elected, Amount Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Hedged Items In Fair Value Hedging Relationship [Table] Hedged Items In Fair Value Hedging Relationship [Table] Table shows the carrying amount and associated cumulative basis adjustment related to the application of hedge accounting that is included in the carrying amount of hedged assets and liabilities in fair value hedging relationships. Carrying Amount of Assets Goodwill, Gross Financial Instruments [Domain] Financial Instruments [Domain] Due > 10 Years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10 Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Finance lease liabilities Financial Lease Liabilities [Member] Financial Lease Liabilities Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Carrying Amount of Assets Intangible Assets Gross Including Goodwill Intangible Assets Gross Including Goodwill International card businesses International Card Business [Member] International Card Business Realized gains (losses) reclassified from AOCI into net income Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Minimum Minimum Minimum [Member] Net interest income after provision for credit losses Interest Income (Expense), after Provision for Loan Loss Accrued interest receivable Financing Receivable, Accrued Interest, before Allowance for Credit Loss Company Selected Measure Name Company Selected Measure Name Total other VIEs Nonsecuritization-Related Variable Interest Entities [Member] Nonsecuritization-Related Variable Interest Entities Fair Value Measurement [Domain] Fair Value Measurement [Domain] Loans held for investment Gain (Loss) On Fair Value Loans Held For Investment Recognized In Earnings Gain (Loss) On Fair Value Loans Held For Investment measured on nonrecurring basis Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Depositary Shares, Each Representing a 1/40th Interest in a Share of Fixed Rate Non-Cumulative Perpetual Preferred Stock, Series K Series K Series K Preferred Stock [Member] Outstanding nonredeemable series K preferred stock or outstanding series K preferred stock. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer. Carrying Amount of Assets Mortgage Servicing Asset at Amortized Cost, Gross Mortgage Servicing Asset at Amortized Cost, Gross Affordable housing entities Affordable Housing Entities [Member] The Company invests in affordable housing properties. Affordable housing VIEs can be corporations, partnerships, trusts, or any other legal structure used for investing in affordable housing properties. The Company consolidates those VIEs in which it has a variable interest, power to direct significant activities of the VIE, and obligation to absorb losses or right to receive benefits that could be significant to the VIE. The Company's exposure to losses is limited to its variable interests. Goodwill [Roll Forward] Goodwill [Roll Forward] > 90 Days and Accruing Financing Receivable, 90 Days or More Past Due, Still Accruing Loans, Including Loans Held for Sale Interest income - Loans [Member] Interest income - Loans [Member] Total weighted-average diluted common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Current Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current Entity Small Business Entity Small Business Due in 1 Year or Less Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value Equity securities Equity Securities, Fair Value Disclosure Equity Securities Classified as Other Assets, Fair Value Disclosure Domestic Credit Card and Commercial Banking Portfolios Domestic Credit Card and Commercial Banking Portfolios [Member] Domestic Credit Card and Commercial Banking Portfolios Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Document Transition Report Document Transition Report Due in 1 Year or Less Debt Securities, Held-to-Maturity, Weighted Average Yield, Maturity, Year One Loan Restructuring Modification Name [Axis] Loan Restructuring Modification Name [Axis] Underlying Securities Award Underlying Securities Amount Equity Component [Domain] Equity Component [Domain] Document Period End Date Document Period End Date Amortization expense (benefit) Amortization of Basis Adjustment on Discontinued Hedges Amortization of Basis Adjustment on Discontinued Hedges Total cash and cash equivalents Cash, Cash Equivalents, and Federal Funds Sold Equity investments accounted for under measurement alternative Investments in Affiliates, Subsidiaries, Associates, and Joint Ventures, Fair Value Disclosure Geographic Distribution [Domain] Geographic Distribution [Domain] Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Net Exposure Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Variable interest entity, nonconsolidated Variable Interest Entity, Nonconsolidated, Total Assets Variable Interest Entity, Nonconsolidated, Total Assets Weighted-average expected life Debt Maturities, Available-for-Sale, Weighted Average Expected Life Debt Maturities, Available-for-Sale, Weighted Average Expected Life Document Type Document Type Level 3 Fair Value, Inputs, Level 3 [Member] Earnings Per Common Share Earnings Per Share [Text Block] 1.650% Senior Notes Due 2029 Senior Notes Due 2029 [Member] 1.650% Senior Notes Due 2029 Name Outstanding Recovery, Individual Name Loss Contingencies [Table] Loss Contingencies [Table] Additional paid-in capital, net Additional Paid in Capital Product and Service [Axis] Product and Service [Axis] Revolving Loans Financing Receivable, Excluding Accrued Interest, Revolving, Writeoff Total contract revenue Revenue from Contract with Customer, Excluding Assessed Tax Treasury stock, par value (in dollars per share) Treasury Stock, Par Value Treasury Stock, Par Value Credit Card Credit Card Segment [Member] Credit Card Segment Statistical Measurement [Axis] Statistical Measurement [Axis] Loss contingency accrual Loss Contingency Accrual Credit Score, FICO [Domain] Credit Score, FICO [Domain] Term loan by year, year 2 Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year, Writeoff Class of Securities [Axis] Class of Securities [Axis] Class of Securities Fair Value Measurement Inputs and Valuation Techniques [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Percentage, 90 Days Past Due and Accruing Financing Receivable, Percent 90 Days Past Due and Still Accruing Financing Receivable, Percent 90 Days Past Due and Still Accruing Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Due > 1 Year through 5 Years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value Net income available to common stockholders Net Income (Loss) Available to Common Stockholders, Basic Service charges and other customer-related fees Service Charges And Other Customer Fees, Contracts [Member] Service Charges And Other Customer Fees, Contracts [Member] Entity Information [Line Items] Entity Information [Line Items] Other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Interest rate reduction and term extension Extended Maturity and Interest Rate Reduction [Member] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Gains (Losses) on Free-Standing Derivatives Derivative Instruments, Gain (Loss) [Table Text Block] Level 1 Fair Value, Inputs, Level 1 [Member] Liquidation Preference per Share (in dollars per share) Preferred Stock, Redemption Price Per Share Net income (loss) per diluted common share (in dollars per share) Earnings Per Share, Diluted Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Long lived assets held for sale Long-Lived Asset, Held-for-Sale, Fair Value Disclosure Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Total loans modified Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount Dividends—preferred stock Dividends, Preferred Stock, Cash VIE, nonconsolidated, carrying amount of liabilities included in certain investment structures Variable Interest Entities, nonconsolidated, Carrying amount of liabilities included in certain investment structures In certain investment structures, we consolidate a VIE which in turn holds as its primary asset an investment in an unconsolidated VIE. This concept represents the carrying amount of liabilities related to these investment structures. Hedged Item in Fair Value Hedging Relationship Hedged Item in Fair Value Hedging Relationship [Table Text Block] Table shows the carrying amount and associated cumulative basis adjustment related to the application of hedge accounting that is included in the carrying amount of hedged assets and liabilities in fair value hedging relationships. Treasury stock, shares (in shares) Treasury Stock, Common, Shares Net income (expense) recognized on cash flow hedges Gain (Loss) On Cash Flow Hedges Recognized In Earnings Total amount of gain (loss) derived from cash flow hedges recognized in earnings in the period Consolidation Items [Domain] Consolidation Items [Domain] Derivative Liability, Statement of Financial Position [Extensible Enumeration] Derivative Liability, Statement of Financial Position [Extensible Enumeration] Investments, Debt and Equity Securities [Abstract] Investments, Debt and Equity Securities [Abstract] Core deposit Core Deposits [Member] Unconsolidated Variable Interest Entity, Not Primary Beneficiary [Member] Depositary Shares, Each Representing a 1/40th Interest in a Share of Fixed Rate Non-Cumulative Perpetual Preferred Stock, Series N Series N Series N Preferred Stock [Member] Series N Preferred Stock Term extension Extended Maturity [Member] Financing Receivable Portfolio Segment [Axis] Financing Receivable Portfolio Segment [Axis] Total Gains or (Losses) (Realized/Unrealized), Included in Net Income Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings Other Modifications Other Modifications [Member] Other Modifications Weighted-average yield for investment securities held to maturity Debt Securities, Held-to-Maturity, Weighted Average Yield, Maturity [Abstract] Income taxes paid Income Taxes Paid, Net 2028 Finite-Lived Intangible Asset, Expected Amortization, Year Two Collaborative Arrangement and Arrangement Other than Collaborative [Table] Collaborative Arrangement and Arrangement Other than Collaborative [Table] Total unfunded lending commitments, contractual amount Letter of Credit Issued Contractual Amount and Unused Commitment to Extend Credit Letter of credit issued contractual amount and unused commitment to extend credit Due > 5 Years through 10 Years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value Total loans held for investment Total Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss Other: Accumulated Other Comprehensive Income (Loss), Other Component [Member] Accumulated other comprehensive income or loss from pension, other postretirement benefit plans, and others. Net Amounts as Recognized Securities Sold under Agreements to Repurchase Brand / Trade names Trade Names [Member] Schedule of Available-for-Sale Securities in Gross Unrealized Loss Position Debt Securities, Available-for-Sale, Unrealized Loss Position, Fair Value [Table Text Block] Expiration Date Trading Arrangement Expiration Date Total Loans Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months Financing Receivable, Excluding Accrued Interest, Modified, after 12 Months Changes in other liabilities Increase (Decrease) in Other Operating Liabilities 2031 Finite-Lived Intangible Asset, Expected Amortization, Year Five Changes in other borrowings Proceeds from (Repayments of) Other Debt Allowance for Credit Losses Debt Securities, Held-to-Maturity, Allowance for Credit Loss, Excluding Accrued Interest Other Other Investments [Member] Premises and equipment, net Property, Plant and Equipment, Net Net unrealized gains (losses) on investment securities available for sale Net unrealized gains (losses) on securities available for sale Other Comprehensive Income (Loss), Available-for-Sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Common stock: Payments of Ordinary Dividends [Abstract] Entity Current Reporting Status Entity Current Reporting Status Due in 1 Year or Less Debt Securities, Available-for-Sale, Maturity, Rolling within One Year, Weighted Average Yield Receivables [Abstract] Receivables [Abstract] Life of receivables (months) Measurement Input, Life of Receivables [Member] Measurement input using life of receivables Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Consolidated Entities [Domain] Consolidated Entities [Domain] Credit card marketing expense Credit Card Marketing Expense Credit Card Marketing Expense Derivative liabilities, gross amount Gross Amounts Derivative Liability, Gross Liability Including Not Subject to Master Netting Arrangement Financial Instrument [Axis] Financial Instrument Financial Instrument [Axis] Adjustments to reconcile net income to net cash from operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Noncash Item [Abstract] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Executive Category: Executive Category [Axis] Gross Unrealized Loss - 12 Months or Longer Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Depositary Shares, Each Representing a 1/40th Interest in a Share of Fixed Rate Non-Cumulative Perpetual Preferred Stock, Series J Series J Series J Preferred Stock [Member] Outstanding nonredeemable series J preferred stock or outstanding series J preferred stock. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer. Interest income (expense) Interest Expense, Operating and Nonoperating Current Fiscal Year End Date Current Fiscal Year End Date Gross Unrealized Loss - Less than 12 Months Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Total deposits Deposits Deposits Net Amounts as Recognized Derivative liability Derivative Liability Other Other Noninterest Expense Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Loan Restructuring Modification [Axis] Loan Restructuring Modification [Axis] Noncriticized Pass [Member] Interest rate contracts: Interest Rate Contract [Member] Securitized debt obligations Securitized Debt Obligations Interest Expense, Secured Debt Interest Expense, Secured Debt Delinquent Loans Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Noncurrent Gross Unrealized Loss - Total Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Dividends—common stock (in shares) Common Stock Dividends, Shares Cash and cash equivalents: Cash and Cash Equivalents [Abstract] Anti-dilutive options excluded from the computation of diluted earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Loan Portfolio Composition and Aging Analysis Financing Receivable, Past Due [Table Text Block] Interest-bearing deposits Interest-Bearing Deposit Liabilities Net cash from (used in) financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Measure: Measure [Axis] Provision for credit losses Provision for credit losses Change in estimated partner reimbursements that decreased provision for credit losses Financing Receivable, Credit Loss, Expense (Reversal) Valuation Approach and Technique [Axis] Valuation Approach and Technique [Axis] Thereafter Finite-Lived Intangible Asset, Expected Amortization, after Year Five Liabilities: Financial Liabilities Fair Value Disclosure [Abstract] Due > 5 Years through 10 Years Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value Consumer Banking: Consumer Portfolio Segment [Member] Reclassifications from AOCI Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Due > 10 Years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Total Gain (Loss) On Fair Value Assets Recognized In Earnings Gain (Loss) On Fair Value Assets measured on nonrecurring basis Entity Tax Identification Number Entity Tax Identification Number Discounted cash flows Valuation Technique, Discounted Cash Flow [Member] Other adjustments Goodwill, Other Increase (Decrease) Term loan by year, year 4 Financing Receivable, Excluding Accrued Interest, Year Four, Originated, Three Years before Current Fiscal Year, Writeoff Carrying Amount of Assets and Liabilities of Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Non-Interest Income, Other Non Interest Income Other [Member] Non Interest Income Other Member Common stock, shares issued (in shares) Common Stock, Shares, Issued Carrying Amount Assets Carrying Amount Of Assets Carry amount of assets hedged in fair value hedging relationship Derivative Asset, Statement of Financial Position [Extensible Enumeration] Derivative Asset, Statement of Financial Position [Extensible Enumeration] CMBS Commercial Mortgage-Backed Securities [Member] Goodwill and Other Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Other borrowings Interest Expense Other Borrowings Interest expense incurred during the reporting period on other borrowings. Goodwill by Business Segments Schedule of Goodwill [Table Text Block] Trading Arrangement: Trading Arrangement [Axis] Total Shareholder Return Amount Total Shareholder Return Amount Repurchase agreements Offsetting Securities Sold under Agreements to Repurchase [Abstract] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Retained interests in securitizations Retained Interest [Member] Current Financial Asset, Current And Less Than 30 Days Past Due [Member] Financial Asset, Current And Less Than 30 Days Past Due [Member] Other Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Security Exchange Name Security Exchange Name Senior and Subordinated Notes Interest expense - Senior and Subordinated Debt [Member] Interest expense - Senior and Subordinated Debt [Member] Goodwill Goodwill, Impaired, Accumulated Impairment Loss [Abstract] Standby letters of credit and commercial letters of credit, contractual amount Line of Credit Facility, Maximum Borrowing Capacity Indefinite-Lived Intangible Assets, Major Class Name [Domain] Indefinite-Lived Intangible Assets, Major Class Name [Domain] Foreclosed property and repossessed assets, fair value disclosure Foreclosed Property and Repossessed Assets, Fair Value Disclosure Foreclosed property and repossessed assets, fair value disclosure Total Gains or (Losses) (Realized/Unrealized), Included in Net Income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Financing Receivable, Modified, Subsequent Default [Table] Financing Receivable, Modified, Subsequent Default [Table] Schedule of Intangible Assets by Major Class [Line Items] Schedule of Intangible Assets by Major Class [Line Items] [Line Items] for Schedule of Intangible Assets by Major Class [Table] Statement [Line Items] Statement [Line Items] Entity Loan Modification Program Entity Loan Modification Program [Member] Securities Collateral Pledged Under Master Netting Agreements Security Sold under Agreement to Repurchase, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Security Not Offset Investment securities available for sale: Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss [Abstract] Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Retained interests in securitizations Retained Interest, Fair Value Disclosure Credit car lines, contractual amount Unused Commitments to Extend Credit Common Stock (par value $.01 per share) Common Stock Common Stock [Member] Changes in cash, cash equivalents and restricted cash for securitization investors Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Total effect of dilutive securities (in shares) Weighted Average Number of Shares Outstanding, Diluted, Adjustment Statistical Measurement [Domain] Statistical Measurement [Domain] Underlying Asset Class [Axis] Underlying Asset Class [Axis] Securities available for sale, amortized cost Amortized Cost Basis Total Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, before Allowance for Credit Loss RMBS, Non-agency Residential Mortgage Backed Securities, Non-agency [Member] Securities collateralized by non-agency residential real estate mortgage loans. Financing receivable, nonaccrual, interest income Financing Receivable, Nonaccrual, Interest Income Weighted-Average Interest Rate Long-Term Debt, Weighted Average Interest Rate, at Point in Time Carrying Amount of Assets Intangible Assets, Gross (Excluding Goodwill) Valuation Approach and Technique [Domain] Valuation Approach and Technique [Domain] Total investment securities Debt Securities, Available-for-Sale and Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss Total Gains or (Losses) (Realized/Unrealized), Included in OCI Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) 621-660 FICO Score 621 To 660 [Member] FICO Score 621 To 660 [Member] Basic earnings per common share: Earnings Per Share, Basic [Abstract] Number of shares of Capital One treasury stock issued in the acquisition (in shares) Business Combination, Consideration Transferred, Equity Interest, Share Issued, Number of Shares Restricted cash for securitization investors Restricted Cash and Cash Equivalents, Fair value Disclosure Restricted Cash and Cash Equivalents, Fair value Disclosure Transfers Into Level 3 Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers into Level 3 Domestic credit card Domestic Card [Member] Domestic Card Gross Unrealized Losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Net income (loss) per basic common share (in dollars per share) Net income per basic common share (in dollars per share) Earnings Per Share, Basic Series M Series M Preferred Stock [Member] Outstanding nonredeemable series M preferred stock or outstanding series M preferred stock. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer. Discount rate Measurement Input, Discount Rate [Member] Schedule of Segment Results and Reconciliation Schedule of Segment Reporting Information, by Segment [Table Text Block] Net loss from discontinued operations (in dollars per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Total short-term borrowings Short-Term Debt Changes in interest receivable Increase (Decrease) in Accrued Interest Receivable, Net Gross Unrealized Gains Debt Securities, Held-to-Maturity, Accumulated Unrecognized Gain Measurement Input Type [Domain] Measurement Input Type [Domain] Schedule of Available-for-Sale Securities Schedule of Available-for-Sale Securities Reconciliation [Table Text Block] Net Unrealized Gains (Losses) Included in Net Income Related to Assets and Liabilities Still Held Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) Brex Inc. Brex Inc. [Member] Brex Inc. Schedule of Assets Measured at Fair Value on Nonrecurring Basis Fair Value Measurements, Nonrecurring [Table Text Block] Total Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff Communications and data processing Communications and Information Technology Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Loans held in consolidated trusts Consolidated Variable Interest Entity, Primary Beneficiary [Member] Financial receivable, non-interest expense Third Party Collections Expense Third Party Collections Expense Securities sold under repurchase agreements, fair value of collateral Securities Sold under Agreements to Repurchase, Fair Value of Collateral Other comprehensive income (loss) before reclassifications OCI, before Reclassifications, Net of Tax, Attributable to Parent Derivative Instruments, Gain (Loss) [Line Items] Derivative Instruments, Gain (Loss) [Line Items] Hedging Designation [Domain] Hedging Designation [Domain] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Securitized debt obligations Secured Debt Loans held for sale ($169 million and $755 million carried at fair value as of March 31, 2026 and December 31, 2025, respectively) Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance Total liabilities and stockholders’ equity Liabilities and Equity Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Amounts reclassified from AOCI into earnings Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Derivative assets Offsetting Derivative Assets [Abstract] Accounting Policies [Abstract] Accounting Policies [Abstract] Due > 10 Years Debt Securities, Available-for-Sale, Maturity, Rolling after 10 Years, Weighted Average Yield Investment securities held to maturity: Debt Securities, Held-to-Maturity, Excluding Accrued Interest, after Allowance for Credit Loss [Abstract] Financial Instruments Security Sold under Agreement to Repurchase, Subject to Master Netting Arrangement, Asset Offset Concentration Risk Type [Domain] Concentration Risk Type [Domain] Maturities and paydowns of long-term debt Repayments of Secured Debt Treasury Stock Treasury Stock, Common [Member] Term Loans by Vintage Year, Year 1 Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year Pay vs Performance Disclosure [Line Items] Loss sharing agreements Loss sharing agreements Loss Sharing Agreement [Member] Loss Sharing Agreement [Member] Foreign currency translation adjustments Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Greater than 90 days Financial Asset, Equal to or Greater than 90 Days Past Due [Member] Liabilities: Liabilities [Abstract] Accrued interest receivable Debt Securities, Available-for-Sale, Change in Present Value, Interest Income Depreciation and amortization, net Depreciation, Depletion and Amortization, Nonproduction Auto Automobile Loan [Member] Allowance for credit losses SEC Schedule, 12-09, Allowance, Loan and Lease Loss [Member] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Gains (losses) recognized on hedged items Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge Schedule of Variable Interest Entities [Table] Variable Interest Entity [Table] Interest-bearing Deposits Interest expense - Deposits [Member] Interest expense - Deposits [Member] Term Loans by Vintage Year, Year 3 Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Company Selected Measure Amount Company Selected Measure Amount Prior Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year, Writeoff Comprehensive income Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Measurement Input Type [Axis] Measurement Input Type [Axis] Name Measure Name Issuances Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances Securitized debt obligations Secured Debt [Member] Other comprehensive income (loss) Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Changes in deposits Increase (Decrease) in Deposits Proceeds from paydowns and maturities Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale Sales Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Sales Class of Stock [Line Items] Class of Stock [Line Items] Income (loss) from discontinued operations, net of tax Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Off-balance sheet lending commitment, carrying value Off-Balance Sheet Lending Commitment Carrying Value The carrying value of off-balance sheet lending-related financial instruments (e.g., commitments and guarantees), which represents the allowance for lending-related commitments, deferred revenue and the guarantee liability. Securitized debt obligations Securitized Debt Obligations [Member] securitized debt obligations [Member] Total Gains or (Losses) (Realized/Unrealized), Included in OCI Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss) Derivative Liability, netting adjustments Derivative Liability, Subject to Master Netting Arrangement, Gross Asset and Collateral, Right to Reclaim Cash, Offset Carrying value Long-Term Debt Total assets Carrying Amount of Assets Assets Assets 2027 Finite-Lived Intangible Asset, Expected Amortization, Year One Interest receivable Interest Receivable, Fair Value Disclosure This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure and may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. This item represents interest earned but not received as of the balance sheet date. Senior and subordinated notes Senior and Subordinated Notes Interest Expense, Unsecured Debt Interest expense incurred during the reporting period on senior and subordinated notes. Financing Receivable, Credit Quality Indicator [Line Items] Financing Receivable, Credit Quality Indicator [Line Items] Total Shares Outstanding (in shares) Preferred Stock, Depositary Shares Issued Preferred Stock, Depositary Shares Issued Net derivative assets (liabilities) Net Derivative Assets (Liabilities) [Member] Net Derivative Assets (Liabilities) Estimated reimbursements from partners, beginning of period Estimated reimbursements from partners, end of period Loss Sharing Agreements, Financing Receivable, Allowance, Covered, Expected Reimbursement Loss Sharing Agreements, Financing Receivable, Allowance, Covered, Expected Reimbursement Allowance for Credit Losses [Roll Forward] Financing Receivable, Allowance for Credit Loss [Roll Forward] Financing Receivable, Allowance for Credit Loss [Roll Forward] Operating activities: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Proceeds from sales and paydowns Proceeds from Sale and Collection, Loan, Held-for-Sale Assets: Assets, Fair Value Disclosure [Abstract] Due > 1 Year through 5 Years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost 2030 Finite-Lived Intangible Asset, Expected Amortization, Year Four Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Credit Score, FICO [Axis] Credit Score, FICO [Axis] Marketing Marketing Expense Dividend per share on common stock declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Revenue (reduction) from other sources Noninterest Income, Excluding Revenue From Contract With Customer Noninterest Income, Excluding Revenue From Contract With Customer Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-Sale [Line Items] Basic earnings per common share: Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share [Abstract] Level 2 Fair Value, Inputs, Level 2 [Member] Due > 5 Years through 10 Years Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 5 Through 10 Loans held for sale: Proceeds from Sale, Loan, Held-for-Sale [Abstract] Securitized debt obligations Secured Debt, Fair Value Disclosure Secured Debt, Fair Value Disclosure Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Business Combination [Domain] Business Combination [Domain] Net derivative assets (liabilities), measurement input Derivative Asset (Liability) Net, Measurement Input PEO PEO [Member] Greater than 660 FICO Score Greater Than 660 [Member] FICO Score Greater Than 660 [Member] Transfers Into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Issuance of long-term debt Proceeds from Issuance of Secured Debt Schedule of Contractual Maturities for Securities Investments Classified by Contractual Maturity Date [Table Text Block] Discontinued Hedging Relationships, Assets Hedged Asset, Discontinued Fair Value Hedge, Cumulative Increase (Decrease) Exercises of stock options (in shares) Stock Issued During Period, Shares, Stock Options and Warrants Exercised and Restricted Stock Vesting Stock Issued During Period, Shares, Stock Options and Warrants Exercised and Restricted Stock Vesting Due in 1 Year or Less Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value Changes in operating assets and liabilities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Delinquent Loans, percentage of total loans Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Noncurrent, Percent Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Noncurrent, Percent Retained Earnings Retained Earnings [Member] Cash, cash equivalents and restricted cash for securitization investors, beginning of the period Cash, cash equivalents and restricted cash for securitization investors, end of the period Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement [Abstract] Income Statement [Abstract] Net Amounts as Recognized Derivative asset Derivative Asset Fair Value - 12 Months or Longer Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Fixed unsecured senior debt Fixed Unsecured Senior Debt [Member] Fixed unsecured senior debt. Nonrecurring Fair Value, Nonrecurring [Member] Investment securities available for sale: Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale [Abstract] Other investments Investments, Fair Value Disclosure Changes in interest payable Increase (Decrease) in Interest Payable, Net Other intangible assets Net Carrying Amount Intangible Assets, Net (Excluding Goodwill) Financing Receivable, Troubled Debt Restructuring [Table] Financing Receivable, Modified [Table] Other Non-interest income (expense) Noninterest Income, Other Product and Service [Domain] Product and Service [Domain] Network and financial partner relationships Network and Financial Partner Relationships [Member] Network and Financial Partner Relationships Transfers Out of Level 3 Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers out of Level 3 Net income (loss) from continuing operations (in dollars per share) Income (Loss) from Continuing Operations, Per Diluted Share Ann Fritz Hackett [Member] Ann Fritz Hackett Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Business Combination [Table] Business Combination [Table] Notional or Contractual Amount Derivative, Notional Amount Securities received as collateral Securities Received as Collateral Net valuation allowance on derivative assets and liabilities for non-performance risk Net valuation allowance Derivative Credit Risk Valuation Adjustment, Derivative Assets (Liabilities) Derivative Credit Risk Valuation Adjustment, Derivative Assets (Liabilities) Revolving Loans Financing Receivable, Excluding Accrued Interest, Revolving Realized gain (loss) on foreign exchange contracts reclassified from AOCI Realized Gains (Losses) On Foreign Exchange Contracts Reclassified From AOCI Realized Gains (Losses) On Foreign Exchange Contracts Reclassified From AOCI City Area Code City Area Code Allowance for Credit Losses on Financing Receivables Financing Receivable, Allowance for Credit Loss [Table Text Block] Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Gain (loss) from Litigation Settlement Gain (Loss) from Litigation Settlement Loan Restructuring Modification Name [Domain] Loan Restructuring Modification Name [Domain] Investing activities: Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Retained interests, measurement input, life of receivables Retained Interest, Measurement Input, Life of Receivables Retained Interest, Measurement Input, life of receivables Interest receivable Interest Receivable Fair value hedges Fair Value Hedging [Member] Investment securities available for sale Total investment securities available for sale Debt Securities, Available For Sale [Member] Debt Securities, Available For Sale Total securitization-related VIEs Securitization-Related Variable Interest Entities [Member] Securitization-Related Variable Interest Entities Cash flow hedges Cash Flow Hedging [Member] Other liabilities Other Liabilities Goodwill Net Carrying Amount Goodwill, beginning balance Goodwill, ending balance Goodwill Loss contingency, estimate of possible loss Loss Contingency, Estimate of Possible Loss Kaitlin Haggerty [Member] Kaitlin Haggerty Principal balance reduction Financing Receivable, Modified in Period, Amount Due > 5 Years through 10 Years Debt Securities, Held-to-Maturity, Weighted Average Yield, Maturity, after Year 5 Through 10 Due > 5 Years through 10 Years Debt Securities, Available-for-Sale, Maturity, Rolling after 5 through 10 Years, Weighted Average Yield Transfers Out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Interest recognized on derivatives Gain Or Loss On Fair Value Hedges Recognized In Net Interest Income Gain or loss on fair value hedges recognized in net interest income Supplemental cash flow information: Supplemental Cash Flow Information [Abstract] Beginning balance Ending balance Net derivative assets (liabilities) Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs Preferred Stock Redemption Discount Preferred Stock Redemption Discount Other Performance Measure, Amount Other Performance Measure, Amount US Treasury and Agency securities US Treasury and Government [Member] Investment Securities Marketable Securities, Policy [Policy Text Block] Voluntary prepayment rate Measurement Input, Constant Prepayment Rate [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Fair Value Fair Value of Financial Instruments, Policy [Policy Text Block] Net changes in loans originated as held for investment Payments For (Proceeds From) Sale Of Financing Receivable, Held-For-Investment Payments For (Proceeds From) Sale Of Financing Receivable, Held-For-Investment Financial liabilities: Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Schedule Of Expected Maturity And Weighted Average Yield Of Securities [Table] Schedule Of Expected Maturity And Weighted Average Yield Of Securities [Table] Schedule of expected maturity and weighted average yield of securities. Net cash from investing activities Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Interest paid Interest Paid, Excluding Capitalized Interest, Operating Activity Schedule of Debtor Troubled Debt Restructuring, Subsequent Periods Schedule of Debtor Troubled Debt Restructuring, Subsequent Periods [Table Text Block] Document Fiscal Year Focus Document Fiscal Year Focus Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Hedged Items In Fair Value Hedging Relationship [Line Items] Hedged Items In Fair Value Hedging Relationship [Line Items] [Line Items] for Table shows the carrying amount and associated cumulative basis adjustment related to the application of hedge accounting that is included in the carrying amount of hedged assets and liabilities in fair value hedging relationships. FDIC Special Assessment FDIC Special Assessment [Member] FDIC Special Assessment Deferred compensation plan assets Deferred Compensation Plan Assets Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract] Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract] Carrying Value Reported Value Measurement [Member] Total goodwill and other intangible assets Intangible Assets, Net (Including Goodwill) [Abstract] Business combination, acquisition related costs Business Combination, Acquisition-Related Cost, Expense Loans held for investment, measurement input Loans Held for Investment, Measurement Input Loans held for investment, measurement input Equity [Abstract] Equity [Abstract] Nonperforming Loans Financing Receivable, Nonaccrual Business Segments and Revenue from Contracts with Customers Segment Reporting Disclosure [Text Block] Schedule of Goodwill [Table] Goodwill [Table] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Derivatives not designated as accounting hedges: Not Designated as Hedging Instrument [Member] U.S. Treasury securities US Treasury Securities [Member] Issuances of common stock and restricted stock, net of forfeitures (in shares) Stock Issued During Period, Shares, New Issues and Restricted Stock, Net of Forfeitures (in shares) Stock Issued During Period, Shares, New Issues and Restricted Stock, Net of Forfeitures Total short-term borrowings and long-term debt Debt and Lease Obligation Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Purchases Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Purchases Personal loans Personal Loans [Member] Personal Loans Other securities Other Debt Obligations [Member] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Advised line of credit Advised Line of Credit The contractual amount of line of credit that drawings are subject to our satisfactory evaluation of the customer and are cancelable upon proper notice. Weighted average Weighted Average [Member] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Commercial Banking Commercial Banking Segment [Member] Consists of lending, deposit gathering and treasury management services to commercial real estate and middle market customers. Our Commercial Banking business results also include the results of a national portfolio of small ticket commercial real-estate loans that are in run-off mode. Amortization of intangible assets Amortization of Intangible Assets Securities available-for-sale, measurement input Debt Securities, Available-for-Sale, Measurement Input Change in AOCI Gain (Loss) by Component (Net of Tax) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Criticized nonperforming Nonperforming Financial Instruments [Member] Percentage of total loans Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Percent, Total Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Percent, Total Due > 10 Years Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value Total RMBS Residential Mortgage-Backed Securities [Member] Arrangement Duration Trading Arrangement Duration Criticized Criticized [Member] Segments [Axis] Segments [Axis] Schedule of Earnings Related to Assets Measured at Fair Value on Nonrecurring Basis Fair Value Assets Measured On Non Recurring Basis Gain Loss Included In Earnings [Table Text Block] Fair Value Assets Measured On Non Recurring Basis Gain Loss Included In Earnings [Table Text Block] Local Phone Number Local Phone Number Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Collaborative Arrangement and Arrangement Other than Collaborative [Domain] Federal funds purchased and securities loaned or sold under agreements to repurchase Federal Funds Purchased and Securities Sold under Agreements to Repurchase Assets: Assets [Abstract] Credit Facility [Axis] Credit Facility [Axis] Other contracts Other Contract [Member] Underlying Security Market Price Change Underlying Security Market Price Change, Percent Debt Instrument [Axis] Debt Instrument [Axis] Due > 1 Year through 5 Years Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value Fair Value Measurement Fair Value Disclosures [Text Block] Business Combination [Line Items] Business Combination [Line Items] Credit Facility [Domain] Credit Facility [Domain] Debt and equity securities, unrealized gain (loss) Debt and Equity Securities, Unrealized Gain (Loss) Stockholders’ equity: Equity, Attributable to Parent [Abstract] Investment Securities Interest income - Investment securities [Member] Interest income - Investment securities [Member] FDM Disclosures Financing Receivable, Modified [Table Text Block] Purchases of treasury stock Treasury Stock, Value, Acquired, Cost Method Stated Interest Rates Debt Instrument, Interest Rate, Stated Percentage 30-59 days Financial Asset, 30 to 59 Days Past Due [Member] Other intangible assets (definite lived): Intangible Assets, Net (Excluding Goodwill) [Abstract] Other Other Comprehensive Income (Loss), Other Tax, Attributable To Parent Other Comprehensive Income (Loss), Other Tax, Attributable To Parent Commitments, Contingencies, Guarantees and Others Commitments Contingencies and Guarantees [Text Block] Commitments to lend on loans modified in TDRs Financing Receivable, Modified, Commitment to Lend Entity Registrant Name Entity Registrant Name Gain (loss) (net after-tax) recorded in AOCI related to derivatives designated as cash flow hedges expected to be reclassified to earnings over the next 12 months Cash Flow Hedge Gain (Loss) to be Reclassified within 12 Months Federal Reserve Discount Window Federal Reserve Discount Window [Member] Federal Reserve Discount Window [Member] Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Schedule Of Expected Maturity And Weighted Average Yield Of Securities [Line Items] Schedule Of Expected Maturity And Weighted Average Yield Of Securities [Line Items] Schedule of expected maturity and weighted average yield of securities line items. Service charges and other customer-related fees Service Charges and Other Customer-Related Fees Amount of income earned from loan services (including debt and credit protection, over limit, membership and annual fees). Excludes interest income earned on credit card balances and transactions. Total Assets, Fair Value Disclosure Number of securities in gross unrealized loss positions Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions Deposits: Deposits [Abstract] Total Delinquent Loans Financial Asset, Past Due [Member] Number of operating segments Number of Operating Segments Components of Deposits, Short-Term Borrowings and Long-Term Debt Schedule of Debt [Table Text Block] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Collaborative Arrangement and Arrangement Other than Collaborative [Axis] Restatement Determination Date: Restatement Determination Date [Axis] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Total other long-term borrowings Other Long Term Borrowings [Member] Other Long Term Borrowings Due > 5 Years through 10 Years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost All Currencies [Domain] All Currencies [Domain] Originations and purchases Payment for Origination and Purchase, Loan, Held-for-Sale Name Trading Arrangement, Individual Name Underlying Asset Class [Domain] Underlying Asset Class [Domain] Schedule of Short-term Debt [Table] Short-Term Debt [Table] Financing receivable, modified, subsequent default Amount Financing Receivable, Modified, Subsequent Default Loans held for sale Loan, Held-for-Sale, Fair Value Disclosure Senior and subordinated notes Unsecured Debt, Fair Value Disclosure Unsecured Debt, Fair Value Disclosure Due > 1 Year through 5 Years Debt Securities, Available-for-Sale, Maturity, Rolling after One Through Five Years, Weighted Average Yield Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Preferred Stock Preferred Stock [Member] Schedule of Loss Sharing Arrangement Impact Schedule of Loss Sharing Arrangement Impact [Table Text Block] Schedule of loss sharing arrangement impact Name Awards Close in Time to MNPI Disclosures, Individual Name Excluded component of fair value hedges Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net Other interest rate exposures Other Interest Rate Exposures [Member] Non-customer accommodation interest rate derivatives not designated as hedging instruments. Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Net Exposure Security Sold under Agreement to Repurchase, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Compensation expense for restricted stock units APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Securities Collateral Pledged Under Master Netting Agreements Derivative Liability, Fair Value of Collateral Unamortized premiums and discounts, deferred fees and costs Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums Litigation Case [Axis] Litigation Case [Axis] Segments [Domain] Segments [Domain] Income Statement Location [Axis] Statement of Income Location, Balance [Axis] Other Other Loan Modifications [Member] Other Loan Modifications Remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Investment Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Agency CMBS Commercial Mortgage Backed Securities - Agency [Member] Commercial Mortgage Backed Securities - Agency [Member] Balance Sheet Location [Domain] Statement of Financial Position Location, Balance [Domain] Securities Available for Sale Securities available for sale: AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member] Derivative, collateral, obligation to return cash Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash Not Offset Interest expense: Interest Expense, Operating and Nonoperating [Abstract] Allowance build (release) for credit losses Allowance build (release) for credit losses Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease) Revenue from Contracts with Customers Revenue [Policy Text Block] Financial Instruments Derivative Liability, Subject to Master Netting Arrangement, Asset Offset Senior notes Senior Notes [Member] Purchases Payments to Acquire Debt Securities, Available-for-Sale Preferred stock (par value $0.01 per share; 50,000,000 shares authorized; 4,980,700 shares issued and outstanding as of both March 31, 2026 and December 31, 2025) Preferred Stock, Value, Issued Interest payable Interest Payable Term Loans by Vintage Year, Year 2 Financing Receivable, Excluding Accrued Interest, Year Two, Originated, Fiscal Year before Current Fiscal Year Proceeds from share-based payment activities Proceeds from Stock Plans Fair value of investment securities held to maturity Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract] Subordinated notes Subordinated Debt [Member] Financial Asset, Period Past Due [Axis] Financial Asset, Aging [Axis] All Executive Categories All Executive Categories [Member] Interest and fees forgiven Financing Receivable, Modified in Period, Accrued Interest, Amount Other changes Financing Receivable, Allowance For Credit Loss, Adjustments, Other Financing Receivable, Allowance For Credit Loss, Adjustments, Other Common stock (par value $0.01 per share; 1,000,000,000 shares authorized; 712,695,412 and 708,546,381 shares issued as of March 31, 2026 and December 31, 2025, respectively; 615,856,605 and 625,102,271 shares outstanding as of March 31, 2026 and December 31, 2025, respectively) Common Stock, Value, Issued Loans, including loans held for sale Loans, Including Loans Held for Sale Interest and Fee Income, Loans and Leases Gains (losses) recognized on derivatives Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Business combination, consideration transferred, equity interest, share issued, value Business Combination, Consideration Transferred, Equity Interest, Share Issued, Value Federal funds purchased and securities loaned or sold under agreements to repurchase Federal Funds Purchased and Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure Commitments, contingencies and guarantees (see Note 14) Commitments and Contingencies Term loan by year, year 1 Financing Receivable, Excluding Accrued Interest, Year One, Originated, Current Fiscal Year, Writeoff Other Other Comprehensive Income (Loss), Before Tax, Attributable To Parent Other Comprehensive Income (Loss), Other, Before Tax, Attributable To Parent Other assets Gain (Loss) On Fair Value Other Assets Recognized In Earnings Gain (Loss) On Fair Value Other Assets measured on nonrecurring basis Business Combination [Axis] Business Combination [Axis] Short-Term Debt [Line Items] Short-Term Debt [Line Items] Total Liabilities Hedged Liability, Fair Value Hedge, Cumulative Increase (Decrease) Net charge-offs Financing Receivable, Allowance for Credit Loss, Writeoff, after Recovery PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Diluted earnings per common share: Earnings Per Share, Diluted [Abstract] Total Term Loans Financing Receivable, Excluding Accrued Interest, Before Allowance for Credit Loss, Term Loans Financing Receivable, Excluding Accrued Interest, Before Allowance for Credit Loss, Term Loans 60-89 days Financial Asset, 60 to 89 Days Past Due [Member] Hedging Designation [Axis] Hedging Designation [Axis] Effects of Fair Value and Cash Flow Hedge Accounting Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location [Table Text Block] Other Other Other Interest and Dividend Income Discount and interchange fees, net Interchange Fees, Net Revenues earned from switch fees charged to financial institutions for accessing our network to process transactions and other fees, net of reward costs. Loans held for sale Gain (Loss) On Fair Value Loans Held For Sale Recognized In Earnings Gain (Loss) On Fair Value Loans Held For Sale measured on nonrecurring basis Net Exposure Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Other comprehensive gain (loss) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax Net investment hedges Net investment hedges Net Investment Hedging [Member] Derivative Contract [Domain] Derivative Contract [Domain] Financing Receivable, Allowance for Credit Loss [Table] Financing Receivable, Allowance for Credit Loss [Table] Net proceeds from issuances Proceeds from Issuance of Common Stock All Individuals All Individuals [Member] Issuances Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Issues Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Discover Network Network [Member] Network Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Changes in premises and equipment Payments to Acquire Property, Plant, and Equipment Name Forgone Recovery, Individual Name Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Retained interests, measurement input Retained Interest, Measurement Input Value of input used to measure portion of interest continued to be held by a transferor after transferring financial assets to a third party Nonperforming Loans Without an Allowance Financing Receivable, Nonaccrual, No Allowance Domestic credit card: Geographic Distribution, Domestic [Member] Federal funds purchased and securities loaned or sold under agreements to repurchase Federal Funds Purchased and Securities Sold under Agreements to Repurchase [Member] Government Contracts Concentration Risk Government Contracts Concentration Risk [Member] Revolving loans converted to term during period Financing Receivable, Revolving, Converted to Term Loan During Period Term loan by year, year 5 Financing Receivable, Excluding Accrued Interest, Year Five, Originated, Four Years before Current Fiscal Year, Writeoff Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Other borrowings Other Borrowings Commercial Banking: Commercial Portfolio Segment [Member] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Cash Collateral Pledged Repurchase Agreement, Collateral, Right To Reclaim Cash, Offset Repurchase agreement, collateral, right to reclaim cash, offset Credit card loan securitizations Credit Card Receivable [Member] 620 or below FICO Score, Less Than 620 [Member] FICO Score, Less Than 620 [Member] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Title of 12(b) Security Title of 12(b) Security Due in 1 Year or Less Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost Other comprehensive income (loss), net of tax: After Tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Earnings Per Share [Abstract] Earnings Per Share [Abstract] Term loan by year, year 3 Financing Receivable, Excluding Accrued Interest, Year Three, Originated, Two Years before Current Fiscal Year, Writeoff Net income (expense) recognized on fair value hedges Gain (Loss) on Fair Value Hedges Recognized in Earnings Short-term Debt, Type [Axis] Short-Term Debt, Type [Axis] Combined allowance and reserve Combined Allowance And Unfunded Reserve [Member] Combined allowance and unfunded reserve. Total Debt Securities, Available-for-Sale, Weighted Average Yield Class of Securities [Domain] Security Class [Domain] [Domain] for Security Class Amortization of intangibles Amortization and Impairment of Intangibles Amortization and impairment of Intangibles Effect of dilutive securities: Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Financing Receivable, Allowance for Credit Loss [Line Items] Financing Receivable, Allowance for Credit Loss [Line Items] Award Timing Disclosures [Line Items] Other Interest income - Other [Member] Interest income - Other [Member] Measurement Frequency [Domain] Measurement Frequency [Domain] Short-term FHLB advances FHLB advances Federal Home Loan Bank Advances [Member] Variable Interest Entities and Securitization [Abstract] Variable Interest Entities and Securitization [Abstract] Variable Interest Entities and Securitization [Abstract] Loss severity Measurement Input, Loss Severity [Member] Total Delinquent Loans, percentage of total loans Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Noncurrent, Percent, Total Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Noncurrent, Percent, Total Gross Amounts Security Sold under Agreement to Repurchase, Subject to Master Netting Arrangement, before Offset Consumer Banking Consumer Banking Segment [Member] Consists of our branch-based lending and deposit gathering activities for small business customers, as well as branch-based consumer deposit gathering and lending activities, national deposit gathering, national automobile lending, consumer mortgage lending and servicing activities. Stockholders' Equity Equity [Text Block] Loan Restructuring Modification [Domain] Loan Restructuring Modification [Domain] Issuances of common stock and restricted stock, net of forfeitures Stock Issued During Period, Value, New Issues and Restricted Stock, Net of Forfeitures Stock Issued During Period, Value, New Issues and Restricted Stock, Net of Forfeitures Net income Net income Net income Net Income (Loss) Attributable to Parent Current, percentage of total loans Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current, Percent, Total Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Current, Percent, Total Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Purchases of treasury stock Payments for Repurchase of Common Stock Adoption Date Trading Arrangement Adoption Date Percentage, Nonperforming Loans Without an Allowance Financing Receivable, Nonaccrual, No Allowance, Percent Past Due Financing Receivable, Nonaccrual, No Allowance, Percent Past Due Financing Receivable, Past Due [Table] Financing Receivable, Past Due [Table] Interest-bearing deposits Interest-Bearing Deposits [Member] Weighted-average yield for investment securities available for sale Available-for-sale Securities, Weighted Average Yield [Abstract] Available-for-sale Securities, Weighted Average Yield [Abstract] Depositary Shares, Each Representing a 1/40th Interest in a Share of Fixed Rate Non-Cumulative Perpetual Preferred Stock, Series L Series L Series L Preferred Stock [Member] Outstanding nonredeemable series L preferred stock or outstanding series L preferred stock. Classified within stockholders' equity if nonredeemable or redeemable solely at the option of the issuer. Classified within temporary equity if redemption is outside the control of the issuer. Purchased credit card relationships Customer Relationships [Member] Offsetting Liabilities Offsetting Liabilities [Table Text Block] Retained earnings Retained Earnings (Accumulated Deficit) Interchange fees, net Interchange Fees, Contracts [Member] Interchange Fees, Contracts [Member] Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Uncollectible portion of billed finance charges and fees Uncollectible Portion of Billed Finance Charges and Fees Uncollectible Portion of Billed Finance Charges and Fees Purchases Payments to Acquire Held-to-Maturity Securities Class of Stock [Axis] Class of Stock [Axis] Hedging relationships: Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Statement [Table] Statement [Table] Deferred tax provision Deferred Income Tax Expense (Benefit) Financing activities: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Total Debt Securities, Held-to-Maturity, Weighted Average Yield Beginning balance (in shares) Ending balance (in shares) Shares, Issued Deposits with defined maturities Deposits with Defined Maturities Deposits with Defined Maturities, Fair Value Disclosure Discount on redeemed preferred stock Discount For Preferred Stock Redeemed Issuance cost for preferred stock redeemed Credit Card: Credit Card Portfolio Segment [Member] Credit Card Portfolio Segment [Member] Retail banking Retail Banking [Member] Any loan or extension of credit to an individual for personal, family, or household. Summary of Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Schedule of Level 3 Inputs Reconciliation Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] All Adjustments to Compensation All Adjustments to Compensation [Member] Interest rate reduction Contractual Interest Rate Reduction [Member] Total Debt Securities, Held-to-Maturity, Maturity, Allocated and Single Maturity Date, Fair Value Amendment Flag Amendment Flag Treasury stock, at cost (par value $0.01 per share; 96,838,807 and 83,444,110 shares as of March 31, 2026 and December 31, 2025, respectively) Treasury Stock, Common, Value Other assets: Other Assets, Fair Value Disclosure [Abstract] Other Assets, Fair Value Disclosure [Abstract] Termination Date Trading Arrangement Termination Date Interest-bearing deposits and other short-term investments Interest-Bearing Deposits in Banks and Other Financial Institutions Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Allowance for credit losses Financing receivable, allowance for credit loss, excluding accrued interest Balance at beginning of the period Balance at the end of the period Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest Total weighted-average basic common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Other borrowings Other Borrowings Fair Value Disclosure This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure and may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. This item represents the aggregate of other miscellaneous borrowings owed by the company as of the balance sheet date. Schedule of Computation of Basic and Diluted Earnings Per Common Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Derivative assets, gross amount Gross Amounts Derivative Asset, Gross Asset Including Not Subject to Master Netting Arrangement Segment Reporting [Abstract] Segment Reporting [Abstract] Total Term Loans Total Term Loans Financing Receivable, Excluding Accrued Interest, Term Writeoff Debt Disclosure [Abstract] Derivative liabilities Offsetting Derivative Liabilities [Abstract] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Consolidated Entities [Axis] Consolidated Entities [Axis] Interest payable Interest Payable Fair Value Disclosure This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure and may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. This item represents accrued interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid as of the balance sheet date. Geographic Distribution [Axis] Geographic Distribution [Axis] Provision (Benefit) Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosure [Abstract] Use of Estimates Use of Estimates, Policy [Policy Text Block] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Other comprehensive income (loss) Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Occupancy and equipment Occupancy, Net Financial Instruments Derivative Asset, Subject to Master Netting Arrangement, Liability Offset Insider Trading Arrangements [Line Items] Prior Financing Receivable, Excluding Accrued Interest, Originated, More than Five Years before Current Fiscal Year Current Financial Asset, Not Past Due [Member] Allowance for credit losses Allowance for Credit Losses Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest Total liabilities Carrying Amount of Liabilities Liabilities Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Currency [Axis] Currency [Axis] Settlements Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements Designated hedged items Financial Asset, Closed Portfolio, Portfolio Layer Method, Amortized Cost Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Loans Loans, Notes, Trade and Other Receivables, Excluding Allowance for Credit Losses [Text Block] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Financial Instrument Performance Status [Domain] Financial Instrument Performance Status [Domain] Discover Card Product Misclassification Discover Card Product Misclassification [Member] Discover Card Product Misclassification Asset-backed Securities Asset-Backed Securities [Member] Consolidation Items [Axis] Consolidation Items [Axis] Counterparty Name [Axis] Counterparty Name [Axis] Fixed unsecured subordinated debt Fixed Unsecured Subordinated Debt [Member] Fixed unsecured subordinated debt. Total senior and subordinated notes Senior and subordinated notes Senior And Subordinated Notes [Member] Senior and subordinated notes. Proceeds from paydowns and maturities Proceeds from Maturities, Prepayments and Calls of Held-to-Maturity Securities Other loan commitments Other Portfolio Segments, Excluding Credit Card [Member] Other Portfolio Segments, Excluding Credit Card [Member] Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Non-NEOs Non-NEOs [Member]