Allowance for Credit Losses (Analysis of the Allowance for Credit Losses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Provision for credit losses	$ 288	$ 340
Allowance for loan and lease losses	2,181		2,256
Commercial and Industrial [Member]
Allowance for credit losses, Beginning balance	433	621
Loans and leases charged-off	(63)	(78)
Recoveries of previous charge-offs	4	4
Provision for credit losses	152	(12)
Allowance for credit losses, Ending balance	526	535
Allowance for loan and lease losses	526		433
Commercial Real Estate - Other [Member]
Allowance for credit losses, Beginning balance	334	446
Loans and leases charged-off	(73)	(68)
Recoveries of previous charge-offs	3	3
Provision for credit losses	30	116
Allowance for credit losses, Ending balance	294	497
Allowance for loan and lease losses	294		334
Commercial Real Estate - Residential ADC [Member]
Allowance for credit losses, Beginning balance	286	469
Loans and leases charged-off	(54)	(71)
Recoveries of previous charge-offs	8	4
Provision for credit losses	(34)	19
Allowance for credit losses, Ending balance	206	421
Allowance for loan and lease losses	206		286
Commercial Other Lending Subsidiaries [Member]
Allowance for credit losses, Beginning balance	11	21
Loans and leases charged-off	(3)	(2)
Recoveries of previous charge-offs	1	1
Provision for credit losses	4	(2)
Allowance for credit losses, Ending balance	13	18
Allowance for loan and lease losses	13		11
Direct Retail Lending [Member]
Allowance for credit losses, Beginning balance	232	246
Loans and leases charged-off	(57)	(78)
Recoveries of previous charge-offs	10	9
Provision for credit losses	116	68
Allowance for credit losses, Ending balance	301	245
Allowance for loan and lease losses	301		232
Retail Revolving Credit [Member]
Allowance for credit losses, Beginning balance	112	109
Loans and leases charged-off	(22)	(27)
Recoveries of previous charge-offs	5	5
Provision for credit losses	(1)	18
Allowance for credit losses, Ending balance	94	105
Allowance for loan and lease losses	94		112
Retail Residential Mortgage [Member]
Allowance for credit losses, Beginning balance	365	298
Loans and leases charged-off	(42)	(54)
Recoveries of previous charge-offs	1	1
Provision for credit losses	(23)	83
Allowance for credit losses, Ending balance	301	328
Allowance for loan and lease losses	301		365
Retail Sales Finance [Member]
Allowance for credit losses, Beginning balance	38	47
Loans and leases charged-off	(7)	(10)
Recoveries of previous charge-offs	3	2
Provision for credit losses	(2)	4
Allowance for credit losses, Ending balance	32	43
Allowance for loan and lease losses	32		38
Retail Other Lending Subsidiaries [Member]
Allowance for credit losses, Beginning balance	186	177
Loans and leases charged-off	(57)	(50)
Recoveries of previous charge-offs	6	5
Provision for credit losses	47	43
Allowance for credit losses, Ending balance	182	175
Allowance for loan and lease losses	182		186
Covered and Other Acquired [Member]
Allowance for credit losses, Beginning balance	149	144
Loans and leases charged-off	(15)	0
Recoveries of previous charge-offs	0	0
Provision for credit losses	3	0
Allowance for credit losses, Ending balance	137	144
Allowance for loan and lease losses	137		149
Unallocated [Member]
Allowance for credit losses, Beginning balance	110	130
Loans and leases charged-off	0	0
Recoveries of previous charge-offs	0	0
Provision for credit losses	(15)	0
Allowance for credit losses, Ending balance	95	130
Allowance for loan and lease losses	95		110
Allowance for Loan and Lease Losses [Member]
Allowance for credit losses, Beginning balance	2,256	2,708
Loans and leases charged-off	(393)	(438)
Recoveries of previous charge-offs	41	34
Provision for credit losses	277	337
Allowance for credit losses, Ending balance	2,181	2,641
Reserve For Unfunded Lending Commitments [Member]
Allowance for credit losses, Beginning balance	29	47
Loans and leases charged-off	0	0
Recoveries of previous charge-offs	0	0
Provision for credit losses	11	3
Allowance for credit losses, Ending balance	40	50
Allowance for Credit Losses [Member]
Allowance for credit losses, Beginning balance	2,285	2,755
Loans and leases charged-off	(393)	(438)
Recoveries of previous charge-offs	41	34
Provision for credit losses	288	340
Allowance for credit losses, Ending balance	$ 2,221	$ 2,691