Customer Deposits (Details 1) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
U.S. retail deposits:
Savings accounts - Direct	$ 31,420	$ 30,980
Certificates of deposit - Direct	284	291
Certificates of deposit - Third party	11,617	11,925
Sweep accounts - Third party	9,802	9,120
Other retail deposits:
Non-U.S. deposits and U.S. non-interest bearing deposits	82	110
Card Member credit balances - U.S. and non-U.S.	585	616
Total customer deposits	$ 53,790	$ 53,042