XML 88 R58.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Summary of Significant Accounting Policies - Revenue Recognition (Details) | 12 Months Ended
--- | ---
Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Line Items] |
Loan origination fees and direct loan origination costs amortization period | 12 months
Credit Card: |
Financing Receivable, Allowance for Credit Loss [Line Items] |
Loan origination fees and direct loan origination costs amortization period | 12 months
Amortization term of annual membership fees | 12 months

X
- Definition Amortization term of credit card annual membership fees + References No definition available. + Details
Name: | cof_AmortizationTermofAnnualMembershipFees
Namespace Prefix: | cof_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loan Commitment and Origination Fees and Discounts or Premiums, Amortization Period + References No definition available. + Details
Name: | cof_LoanCommitmentandOriginationFeesandDiscountsorPremiumsAmortizationPeriod
Namespace Prefix: | cof_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph c -Publisher SEC + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=cof_CreditCardPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |