Allowance for Credit Losses (Breakdown of Recorded Investment in Loans Based on the Method for Determining Allowance) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Individually Evaluated for Impairment	$ 2,683	$ 2,809
Collectively Evaluated for Impairment	106,645	102,536
Loans Acquired With Deteriorated Credit Quality	1,747	2,124
Total loans and leases held for investment	111,075	107,469
Commercial and Industrial [Member]
Individually Evaluated for Impairment	691	656
Collectively Evaluated for Impairment	36,247	35,759
Total loans and leases held for investment	36,938	36,415
Commercial Real Estate - Other [Member]
Individually Evaluated for Impairment	413	511
Collectively Evaluated for Impairment	10,044	10,178
Total loans and leases held for investment	10,457	10,689
Commercial Real Estate - Residential ADC [Member]
Individually Evaluated for Impairment	272	420
Collectively Evaluated for Impairment	1,318	1,641
Total loans and leases held for investment	1,590	2,061
Commercial Other Lending Subsidiaries [Member]
Individually Evaluated for Impairment	8	5
Collectively Evaluated for Impairment	4,143	3,621
Total loans and leases held for investment	4,151	3,626
Direct Retail Lending [Member]
Individually Evaluated for Impairment	154	165
Collectively Evaluated for Impairment	15,001	14,302
Total loans and leases held for investment	15,155	14,467
Retail Revolving Credit [Member]
Individually Evaluated for Impairment	58	62
Collectively Evaluated for Impairment	2,148	2,150
Total loans and leases held for investment	2,206	2,212
Retail Residential Mortgage [Member]
Individually Evaluated for Impairment	998	931
Collectively Evaluated for Impairment	22,119	19,650
Total loans and leases held for investment	23,117	20,581
Retail Sales Finance [Member]
Individually Evaluated for Impairment	17	10
Collectively Evaluated for Impairment	7,777	7,391
Total loans and leases held for investment	7,794	7,401
Retail Other Lending Subsidiaries [Member]
Individually Evaluated for Impairment	72	49
Collectively Evaluated for Impairment	5,612	5,062
Total loans and leases held for investment	5,684	5,111
Covered and Other Acquired [Member]
Individually Evaluated for Impairment	0	0
Collectively Evaluated for Impairment	2,236	2,782
Loans Acquired With Deteriorated Credit Quality	1,747	2,124
Total loans and leases held for investment	$ 3,983	$ 4,906