Allowance for Credit Losses (Breakdown of Recorded Investment in Loans Based on the Method for Determining Allowance) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Individually Evaluated for Impairment	$ 2,795	$ 2,809
Collectively Evaluated for Impairment	103,396	102,536
Loans Acquired With Deteriorated Credit Quality	1,970	2,124
Total loans and leases held for investment	108,161	107,469
Commercial and Industrial [Member]
Individually Evaluated for Impairment	769	656
Collectively Evaluated for Impairment	35,387	35,759
Total loans and leases held for investment	36,156	36,415
Commercial Real Estate - Other [Member]
Individually Evaluated for Impairment	418	511
Collectively Evaluated for Impairment	10,125	10,178
Total loans and leases held for investment	10,543	10,689
Commercial Real Estate - Residential ADC [Member]
Individually Evaluated for Impairment	345	420
Collectively Evaluated for Impairment	1,478	1,641
Total loans and leases held for investment	1,823	2,061
Commercial Other Lending Subsidiaries [Member]
Individually Evaluated for Impairment	11	5
Collectively Evaluated for Impairment	3,705	3,621
Total loans and leases held for investment	3,716	3,626
Direct Retail Lending [Member]
Individually Evaluated for Impairment	160	165
Collectively Evaluated for Impairment	14,702	14,302
Total loans and leases held for investment	14,862	14,467
Retail Revolving Credit [Member]
Individually Evaluated for Impairment	61	62
Collectively Evaluated for Impairment	2,098	2,150
Total loans and leases held for investment	2,159	2,212
Retail Residential Mortgage [Member]
Individually Evaluated for Impairment	958	931
Collectively Evaluated for Impairment	20,555	19,650
Total loans and leases held for investment	21,513	20,581
Retail Sales Finance [Member]
Individually Evaluated for Impairment	18	10
Collectively Evaluated for Impairment	7,569	7,391
Total loans and leases held for investment	7,587	7,401
Retail Other Lending Subsidiaries [Member]
Individually Evaluated for Impairment	55	49
Collectively Evaluated for Impairment	5,180	5,062
Total loans and leases held for investment	5,235	5,111
Covered and Other Acquired [Member]
Individually Evaluated for Impairment	0	0
Collectively Evaluated for Impairment	2,597	2,782
Loans Acquired With Deteriorated Credit Quality	1,970	2,124
Total loans and leases held for investment	$ 4,567	$ 4,906