Loans and Card Member Receivables - TDR Subsequently Defaulted, Prior to Adoption (Details) account in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) account
Financing Receivable, Modifications [Line Items]
Number of Accounts | account			18
Aggregated Outstanding Balances Upon Default | $	$ 157	$ 97	$ 120
Card Member loans
Financing Receivable, Modifications [Line Items]
Number of Accounts | account			14
Aggregated Outstanding Balances Upon Default | $			$ 81
Card Member receivables
Financing Receivable, Modifications [Line Items]
Number of Accounts | account			3
Aggregated Outstanding Balances Upon Default | $			$ 38
Other Loans
Financing Receivable, Modifications [Line Items]
Number of Accounts | account			1
Aggregated Outstanding Balances Upon Default | $	$ 2	$ 1	$ 1