Customer Deposits (Details 1) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
U.S. retail deposits:
Savings accounts - Direct	$ 30,672	$ 29,023
Certificates of deposit - Direct	290	281
Certificates of deposit - Third party	12,879	13,856
Sweep accounts - Third party	8,926	10,942
Other retail deposits:
Non-U.S. deposits and U.S. non-interest bearing deposits	139	183
Card Member credit balances - U.S. and non-U.S.	594	712
Total customer deposits	$ 53,500	$ 54,997