Loans and ACL (Breakdown of ALLL Based on Method for Determining Allowance) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Individually Evaluated For Impairment	$ 426	$ 411
Collectively Evaluated For Impairment	1,475	1,607
Commercial and Industrial [Member]
Individually Evaluated For Impairment	70	73
Collectively Evaluated For Impairment	389	397
Commercial Real Estate - Other [Member]
Individually Evaluated For Impairment	33	36
Collectively Evaluated For Impairment	169	168
Commercial Real Estate - Residential ADC [Member]
Individually Evaluated For Impairment	10	21
Collectively Evaluated For Impairment	58	79
Commercial Other Lending Subsidiaries [Member]
Individually Evaluated For Impairment	0	1
Collectively Evaluated For Impairment	16	12
Direct Retail Lending [Member]
Individually Evaluated For Impairment	41	59
Collectively Evaluated For Impairment	177	241
Retail Revolving Credit [Member]
Individually Evaluated For Impairment	23	24
Collectively Evaluated For Impairment	90	78
Retail Residential Mortgage [Member]
Individually Evaluated For Impairment	164	130
Collectively Evaluated For Impairment	165	198
Retail Sales Finance [Member]
Individually Evaluated For Impairment	4	6
Collectively Evaluated For Impairment	38	23
Retail Other Lending Subsidiaries [Member]
Individually Evaluated For Impairment	81	61
Collectively Evaluated For Impairment	207	203
Covered [Member]
Collectively Evaluated For Impairment	126	128
Unallocated [Member]
Collectively Evaluated For Impairment	$ 40	$ 80