Customer Deposits (Details 1) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
U.S. retail deposits:
Savings accounts - Direct	$ 57,062	$ 46,394
Certificates of deposit - Direct	2,749	1,854
Certificates of deposit - Third party	7,771	8,076
Sweep accounts - Third party	15,283	16,121
Other deposits:
U.S. non-interest bearing deposits, Other	25	26
Non-US Deposits, Other	23	26
Card Member credit balances - U.S. and non-U.S.	1,892	790
Total customer deposits	$ 84,805	$ 73,287