Loans - 90+ Day Delinquent Loans Accruing Interest and Nonperforming Loans (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Financing Receivable, Past Due [Line Items]
> 90 Days and Accruing	$ 4,391	$ 5,352
Nonperforming Loans	1,789	1,819
Nonperforming Loans Without an Allowance	$ 712	$ 722
Percentage, 90 Days Past Due and Accruing	0.96%	1.18%
Percentage, Nonperforming Loans	0.39%	0.40%
Percentage, Nonperforming Loans Without an Allowance	0.16%	0.16%
Credit Card:
Financing Receivable, Past Due [Line Items]
> 90 Days and Accruing	$ 4,391	$ 5,352
Nonperforming Loans	24	24
Nonperforming Loans Without an Allowance	0	0
Credit Card: \| Personal loans
Financing Receivable, Past Due [Line Items]
> 90 Days and Accruing	42	47
Nonperforming Loans	10	12
Nonperforming Loans Without an Allowance	0	0
Credit Card: \| Domestic credit card:
Financing Receivable, Past Due [Line Items]
> 90 Days and Accruing	4,186	5,148
Nonperforming Loans Without an Allowance	0	0
Credit Card: \| International card businesses:
Financing Receivable, Past Due [Line Items]
> 90 Days and Accruing	163	157
Nonperforming Loans	14	12
Nonperforming Loans Without an Allowance	0	0
Consumer Banking:
Financing Receivable, Past Due [Line Items]
> 90 Days and Accruing	0	0
Nonperforming Loans	564	583
Nonperforming Loans Without an Allowance	7	4
Consumer Banking: \| Auto
Financing Receivable, Past Due [Line Items]
> 90 Days and Accruing	0	0
Nonperforming Loans	546	566
Nonperforming Loans Without an Allowance	0	0
Consumer Banking: \| Retail banking
Financing Receivable, Past Due [Line Items]
> 90 Days and Accruing	0	0
Nonperforming Loans	18	17
Nonperforming Loans Without an Allowance	7	4
Commercial Banking:
Financing Receivable, Past Due [Line Items]
> 90 Days and Accruing	0	0
Nonperforming Loans	1,201	1,212
Nonperforming Loans Without an Allowance	705	718
Commercial Banking: \| Commercial and multifamily real estate
Financing Receivable, Past Due [Line Items]
> 90 Days and Accruing	0	0
Nonperforming Loans	443	320
Nonperforming Loans Without an Allowance	260	191
Commercial Banking: \| Commercial and industrial
Financing Receivable, Past Due [Line Items]
> 90 Days and Accruing	0	0
Nonperforming Loans	758	892
Nonperforming Loans Without an Allowance	$ 445	$ 527

CAPITAL ONE FINANCIAL CORP 10-Q