Loans and ACL (Aging Analysis of Past Due Loans and Leases) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Loans and Leases Excluding Covered Current	$ 109,743	$ 107,611
Loans and Leases Excluding Covered 30-89 Days Past Due	940	1,068
Loans and Leases Excluding Covered 90 Days Or More Past Due	123	167
Nonaccrual Loans and Leases Excluding Covered	1,149	1,380
Total Loans And Leases Excluding Covered Loans	111,955	110,226
Commercial and Industrial [Member]
Loans and Leases Excluding Covered Current	38,209	37,706
Loans and Leases Excluding Covered 30-89 Days Past Due	32	42
Loans and Leases Excluding Covered 90 Days Or More Past Due	3	1
Nonaccrual Loans and Leases Excluding Covered	457	546
Total Loans And Leases Excluding Covered Loans	38,701	38,295
Commercial Real Estate - Other [Member]
Loans and Leases Excluding Covered Current	11,249	11,237
Loans and Leases Excluding Covered 30-89 Days Past Due	10	12
Loans and Leases Excluding Covered 90 Days Or More Past Due	0	0
Nonaccrual Loans and Leases Excluding Covered	181	212
Total Loans And Leases Excluding Covered Loans	11,440	11,461
Commercial Real Estate - Residential ADC [Member]
Loans and Leases Excluding Covered Current	991	1,131
Loans and Leases Excluding Covered 30-89 Days Past Due	2	2
Loans and Leases Excluding Covered 90 Days Or More Past Due	0	0
Nonaccrual Loans and Leases Excluding Covered	65	128
Total Loans And Leases Excluding Covered Loans	1,058	1,261
Commercial Other Lending Subsidiaries [Member]
Loans and Leases Excluding Covered Current	4,372	4,106
Loans and Leases Excluding Covered 30-89 Days Past Due	13	20
Loans and Leases Excluding Covered 90 Days Or More Past Due	4	9
Nonaccrual Loans and Leases Excluding Covered	2	3
Total Loans And Leases Excluding Covered Loans	4,391	4,138
Direct Retail Lending [Member]
Loans and Leases Excluding Covered Current	15,797	15,502
Loans and Leases Excluding Covered 30-89 Days Past Due	123	145
Loans and Leases Excluding Covered 90 Days Or More Past Due	30	38
Nonaccrual Loans and Leases Excluding Covered	119	132
Total Loans And Leases Excluding Covered Loans	16,069	15,817
Retail Revolving Credit [Member]
Loans and Leases Excluding Covered Current	2,292	2,291
Loans and Leases Excluding Covered 30-89 Days Past Due	20	23
Loans and Leases Excluding Covered 90 Days Or More Past Due	13	16
Nonaccrual Loans and Leases Excluding Covered	0	0
Total Loans And Leases Excluding Covered Loans	2,325	2,330
Retail Residential Mortgage [Member]
Loans and Leases Excluding Covered Current	21,918	22,330
Loans and Leases Excluding Covered 30-89 Days Past Due	465	498
Loans and Leases Excluding Covered 90 Days Or More Past Due	68	92
Nonaccrual Loans and Leases Excluding Covered	254	269
Total Loans And Leases Excluding Covered Loans	22,705	23,189
Retail Residential Mortgage [Member] | Government Guaranteed Loans [Member]
Loans and Leases Excluding Covered Current	256	225
Loans and Leases Excluding Covered 30-89 Days Past Due	93	84
Loans and Leases Excluding Covered 90 Days Or More Past Due	244	252
Nonaccrual Loans and Leases Excluding Covered	0	0
Total Loans And Leases Excluding Covered Loans	593	561
Retail Residential Mortgage [Member] | GNMA [Member]
Loans and Leases Excluding Covered 30-89 Days Past Due	5	5
Loans and Leases Excluding Covered 90 Days Or More Past Due	492	517
Total Loans And Leases Excluding Covered Loans	497	522
Retail Sales Finance [Member]
Loans and Leases Excluding Covered Current	8,764	7,663
Loans and Leases Excluding Covered 30-89 Days Past Due	47	56
Loans and Leases Excluding Covered 90 Days Or More Past Due	5	10
Nonaccrual Loans and Leases Excluding Covered	5	7
Total Loans And Leases Excluding Covered Loans	8,821	7,736
Retail Other Lending Subsidiaries [Member]
Loans and Leases Excluding Covered Current	6,151	5,645
Loans and Leases Excluding Covered 30-89 Days Past Due	228	270
Loans and Leases Excluding Covered 90 Days Or More Past Due	0	1
Nonaccrual Loans and Leases Excluding Covered	66	83
Total Loans And Leases Excluding Covered Loans	$ 6,445	$ 5,999