Allowance for Credit Losses (Commercial Credit Exposure Credit Risk Profile by Internal Loan Risk Rating) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Loans and leases	$ 108,161	$ 107,469
Commercial and Industrial [Member]
Loans and leases	36,156	36,415
Commercial and Industrial [Member] | Pass [Member]
Loans and leases	33,196	33,497
Commercial and Industrial [Member] | Special Mention [Member]
Loans and leases	361	488
Commercial and Industrial [Member] | Substandard - Performing [Member]
Loans and leases	1,914	1,848
Commercial and Industrial [Member] | Nonperforming [Member]
Loans and leases	685	582
Commercial Real Estate - Other [Member]
Loans and leases	10,543	10,689
Commercial Real Estate - Other [Member] | Pass [Member]
Loans and leases	8,669	8,568
Commercial Real Estate - Other [Member] | Special Mention [Member]
Loans and leases	129	234
Commercial Real Estate - Other [Member] | Substandard - Performing [Member]
Loans and leases	1,433	1,493
Commercial Real Estate - Other [Member] | Nonperforming [Member]
Loans and leases	312	394
Commercial Real Estate - Residential ADC [Member]
Loans and leases	1,823	2,061
Commercial Real Estate - Residential ADC [Member] | Pass [Member]
Loans and leases	992	1,085
Commercial Real Estate - Residential ADC [Member] | Special Mention [Member]
Loans and leases	40	60
Commercial Real Estate - Residential ADC [Member] | Substandard - Performing [Member]
Loans and leases	479	540
Commercial Real Estate - Residential ADC [Member] | Nonperforming [Member]
Loans and leases	312	376
Commercial Other Lending Subsidiaries
Loans and leases	3,716	3,626
Commercial Other Lending Subsidiaries | Pass [Member]
Loans and leases	3,664	3,578
Commercial Other Lending Subsidiaries | Special Mention [Member]
Loans and leases	4	5
Commercial Other Lending Subsidiaries | Substandard - Performing [Member]
Loans and leases	32	35
Commercial Other Lending Subsidiaries | Nonperforming [Member]
Loans and leases	$ 16	$ 8