Card Balances and Other Loans - Aging (Details) - Card Balances - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Threshold period past due	30 days
Financing receivables, gross	$ 221,074	$ 213,863
Loans and receivables threshold period for write off	180 days
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	$ 145,733	144,324
Loans over 90 days past due and accruing interest	540	434
Non-accruals	276	471
Small Business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	57,315	53,632
Loans over 90 days past due and accruing interest	161	130
Non-accruals	106	177
Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	18,026	15,907
Loans over 90 days past due and accruing interest	0	0
Non-accruals	0	0
Current | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	144,023	142,552
Current | Small Business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	56,587	52,870
30 to 59 Days Past Due | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	532	529
30 to 59 Days Past Due | Small Business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	251	255
60 to 89 Days Past Due | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	382	392
60 to 89 Days Past Due | Small Business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	162	168
90+ Days Past Due | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	796	851
90+ Days Past Due | Small Business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	315	340
90+ Days Past Due | Corporate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables, gross	$ 57	$ 75