Asset Quality (Summary of TDRs) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Troubled debt restructurings (TDRs)	$ 2,416	$ 2,583
Nonperforming [Member]
Troubled debt restructurings (TDRs)	1,208	1,370
Accruing [Member]
Troubled debt restructurings (TDRs)	1,091	1,083
Credit Card [Member]
Troubled debt restructurings (TDRs)	117	130
Total commercial lending [Member]
Troubled debt restructurings (TDRs)	414	542
Total consumer lending [Member]
Troubled debt restructurings (TDRs)	$ 2,002	$ 2,041