Allowance for Credit Losses (Commercial Credit Exposure Credit Risk Profile by Internal Loan Risk Rating) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Loans and leases	$ 114,140	$ 107,469
Commercial and Industrial [Member]
Loans and leases	38,012	36,415
Commercial and Industrial [Member] | Pass [Member]
Loans and leases	35,603	33,497
Commercial and Industrial [Member] | Special Mention [Member]
Loans and leases	201	488
Commercial and Industrial [Member] | Substandard - Performing [Member]
Loans and leases	1,611	1,848
Commercial and Industrial [Member] | Nonperforming [Member]
Loans and leases	597	582
Commercial Real Estate - Other [Member]
Loans and leases	10,913	10,689
Commercial Real Estate - Other [Member] | Pass [Member]
Loans and leases	9,450	8,568
Commercial Real Estate - Other [Member] | Special Mention [Member]
Loans and leases	101	234
Commercial Real Estate - Other [Member] | Substandard - Performing [Member]
Loans and leases	1,103	1,493
Commercial Real Estate - Other [Member] | Nonperforming [Member]
Loans and leases	259	394
Commercial Real Estate - Residential ADC [Member]
Loans and leases	1,454	2,061
Commercial Real Estate - Residential ADC [Member] | Pass [Member]
Loans and leases	945	1,085
Commercial Real Estate - Residential ADC [Member] | Special Mention [Member]
Loans and leases	26	60
Commercial Real Estate - Residential ADC [Member] | Substandard - Performing [Member]
Loans and leases	279	540
Commercial Real Estate - Residential ADC [Member] | Nonperforming [Member]
Loans and leases	204	376
Commercial Other Lending Subsidiaries
Loans and leases	4,115	3,626
Commercial Other Lending Subsidiaries | Pass [Member]
Loans and leases	4,078	3,578
Commercial Other Lending Subsidiaries | Special Mention [Member]
Loans and leases	6	5
Commercial Other Lending Subsidiaries | Substandard - Performing [Member]
Loans and leases	27	35
Commercial Other Lending Subsidiaries | Nonperforming [Member]
Loans and leases	$ 4	$ 8