Customer Deposits - Categorized as Interest or Non-interest Bearing (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
U.S.:
Interest-bearing	$ 128,146	$ 109,119
Non-interest-bearing (includes Card Member credit balances of: 2023, $495; 2022, $605)	557	663
Non-U.S.:
Interest-bearing	12	15
Non-interest-bearing (includes Card Member credit balances of: 2023, $426; 2022, $439)	429	442
Total customer deposits	129,144	110,239
Card Member Credit Balances
U.S.:
Non-interest-bearing (includes Card Member credit balances of: 2023, $495; 2022, $605)	495	605
Non-U.S.:
Non-interest-bearing (includes Card Member credit balances of: 2023, $426; 2022, $439)	$ 426	$ 439