Customer Deposits (Details 1) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
U.S. retail deposits:
Savings accounts - Direct	$ 30,221	$ 29,023
Certificates of deposit - Direct	287	281
Certificates of deposit - Third party	13,460	13,856
Sweep accounts - Third party	9,698	10,942
Other retail deposits:
Non-U.S. deposits and U.S. non-interest bearing deposits	134	183
Card Member credit balances - U.S. and non-U.S.	604	712
Total customer deposits	$ 54,404	$ 54,997