Allowance for Credit Losses (Commercial Credit Exposure Credit Risk Profile by Internal Loan Risk Rating) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Loans and leases	$ 111,075	$ 107,469
Commercial and Industrial [Member]
Loans and leases	36,938	36,415
Commercial and Industrial [Member] | Pass [Member]
Loans and leases	34,200	33,497
Commercial and Industrial [Member] | Special Mention [Member]
Loans and leases	262	488
Commercial and Industrial [Member] | Substandard - Performing [Member]
Loans and leases	1,856	1,848
Commercial and Industrial [Member] | Nonperforming [Member]
Loans and leases	620	582
Commercial Real Estate - Other [Member]
Loans and leases	10,457	10,689
Commercial Real Estate - Other [Member] | Pass [Member]
Loans and leases	8,848	8,568
Commercial Real Estate - Other [Member] | Special Mention [Member]
Loans and leases	113	234
Commercial Real Estate - Other [Member] | Substandard - Performing [Member]
Loans and leases	1,195	1,493
Commercial Real Estate - Other [Member] | Nonperforming [Member]
Loans and leases	301	394
Commercial Real Estate - Residential ADC [Member]
Loans and leases	1,590	2,061
Commercial Real Estate - Residential ADC [Member] | Pass [Member]
Loans and leases	957	1,085
Commercial Real Estate - Residential ADC [Member] | Special Mention [Member]
Loans and leases	32	60
Commercial Real Estate - Residential ADC [Member] | Substandard - Performing [Member]
Loans and leases	360	540
Commercial Real Estate - Residential ADC [Member] | Nonperforming [Member]
Loans and leases	241	376
Commercial Other Lending Subsidiaries
Loans and leases	4,151	3,626
Commercial Other Lending Subsidiaries | Pass [Member]
Loans and leases	4,110	3,578
Commercial Other Lending Subsidiaries | Special Mention [Member]
Loans and leases	6	5
Commercial Other Lending Subsidiaries | Substandard - Performing [Member]
Loans and leases	28	35
Commercial Other Lending Subsidiaries | Nonperforming [Member]
Loans and leases	$ 7	$ 8