Loans and Card Member Receivables - Modifications that Subsequently Defaulted (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	$ 97	$ 120	$ 239
Interest Rate Reduction and Term Extension
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	1
Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	73
Term Extension
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	23
Card Member loans
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default		81	174
Card Member loans | Consumer
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	53
Card Member loans | Small Business
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	20
Card Member loans | Corporate
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	0
Card Member loans | Interest Rate Reduction and Term Extension | Consumer
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	0
Card Member loans | Interest Rate Reduction and Term Extension | Small Business
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	0
Card Member loans | Interest Rate Reduction and Term Extension | Corporate
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	0
Card Member loans | Interest Rate Reduction | Consumer
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	53
Card Member loans | Interest Rate Reduction | Small Business
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	20
Card Member loans | Interest Rate Reduction | Corporate
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	0
Card Member receivables
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default		38	56
Card Member receivables | Consumer
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	9
Card Member receivables | Small Business
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	14
Card Member receivables | Corporate
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	0
Card Member receivables | Interest Rate Reduction and Term Extension | Consumer
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	0
Card Member receivables | Interest Rate Reduction and Term Extension | Small Business
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	0
Card Member receivables | Interest Rate Reduction and Term Extension | Corporate
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	0
Card Member receivables | Term Extension | Consumer
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	9
Card Member receivables | Term Extension | Small Business
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	14
Card Member receivables | Term Extension | Corporate
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	0
Other loans
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	1	$ 1	$ 9
Other loans | Interest Rate Reduction and Term Extension
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	1
Other loans | Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	0
Other loans | Term Extension
Financing Receivable, Modifications [Line Items]
Account balance, modified and subsequent default	$ 0