Loans and Card Member Receivables - TDR Subsequently Defaulted, Prior to Adoption (Details) account in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) account	Dec. 31, 2021 USD ($) account
Financing Receivable, Modifications [Line Items]
Number of Accounts | account		18	32
Aggregated Outstanding Balances Upon Default | $	$ 97	$ 120	$ 239
Card Member loans
Financing Receivable, Modifications [Line Items]
Number of Accounts | account		14	24
Aggregated Outstanding Balances Upon Default | $		$ 81	$ 174
Card Member receivables
Financing Receivable, Modifications [Line Items]
Number of Accounts | account		3	5
Aggregated Outstanding Balances Upon Default | $		$ 38	$ 56
Other loans
Financing Receivable, Modifications [Line Items]
Number of Accounts | account		1	3
Aggregated Outstanding Balances Upon Default | $	$ 1	$ 1	$ 9