Customer Deposits (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
U.S.:
Interest-bearing	$ 83,304	$ 85,583
Non-interest-bearing (includes Card Member credit balances of: 2021, $527; 2020, $576)	553	599
Non-U.S.:
Interest-bearing	18	19
Non-interest-bearing (includes Card Member credit balances of: 2021, $503; 2020, $671)	507	674
Total customer deposits	84,382	86,875
Card Member Credit Balances
U.S.:
Non-interest-bearing (includes Card Member credit balances of: 2021, $527; 2020, $576)	527	576
Non-U.S.:
Non-interest-bearing (includes Card Member credit balances of: 2021, $503; 2020, $671)	$ 503	$ 671