XML 27 R73.htm IDEA: XBRL DOCUMENT v2.4.1.9
Deposits and Borrowings - Additional Information (Detail) (USD $)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Deposits And Borrowings [Line Items]      
Securitized debt obligations $ 12,717,000,000us-gaap_SecuredDebt   $ 11,624,000,000us-gaap_SecuredDebt
Issuance of securitized debt obligations 1,300,000,000us-gaap_ProceedsFromIssuanceOfSecuredDebt    
Maturities of secured debt 175,000,000cof_MaturitiesofSecuredDebt    
Senior and subordinated notes 20,559,000,000us-gaap_UnsecuredDebt   18,684,000,000us-gaap_UnsecuredDebt
Fair value hedging losses 303,000,000cof_DebtInstrumentFairValueHedgingLosses   179,000,000cof_DebtInstrumentFairValueHedgingLosses
Repayments of unsecured debt 1,250,000,000us-gaap_RepaymentsOfUnsecuredDebt 275,000,000us-gaap_RepaymentsOfUnsecuredDebt  
Advances from Federal Home Loan Banks 6,800,000,000us-gaap_AdvancesFromFederalHomeLoanBanks   17,300,000,000us-gaap_AdvancesFromFederalHomeLoanBanks
Other Assets      
Deposits And Borrowings [Line Items]      
Investment in FHLB stock 1,500,000,000us-gaap_FederalHomeLoanBankStock
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherAssetsMember
  2,000,000,000us-gaap_FederalHomeLoanBankStock
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherAssetsMember
Senior notes | Total unsecured senior debt      
Deposits And Borrowings [Line Items]      
Proceeds from issuance of unsecured debt 3,000,000,000us-gaap_ProceedsFromIssuanceOfUnsecuredDebt
/ us-gaap_DebtInstrumentAxis
= cof_UnsecuredSeniorDebtMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
   
Senior notes | Floating unsecured senior debt      
Deposits And Borrowings [Line Items]      
Proceeds from issuance of unsecured debt 400,000,000us-gaap_ProceedsFromIssuanceOfUnsecuredDebt
/ us-gaap_DebtInstrumentAxis
= cof_FloatingUnsecuredSeniorDebtMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
   
Senior notes | Fixed unsecured senior debt      
Deposits And Borrowings [Line Items]      
Proceeds from issuance of unsecured debt $ 2,600,000,000us-gaap_ProceedsFromIssuanceOfUnsecuredDebt
/ us-gaap_DebtInstrumentAxis
= cof_FixedUnsecuredSeniorDebtMember
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember