Customer Deposits (Details 1) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
U.S. retail deposits:
Savings accounts - Direct	$ 28,229	$ 26,159
Certificates of deposit - Direct	291	333
Certificates of deposit - Third party	11,053	7,838
Sweep accounts - Third party	8,940	8,949
Non-U.S. deposits and U.S. non-interest bearing deposits	162	173
Card Member credit balances - U.S. and non-U.S.	626	719
Total customer deposits	$ 49,301	$ 44,171