Allowance for Credit Losses (Analysis of the Allowance for Credit Losses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Provision for credit losses	$ 273	$ 328	$ 561	$ 668
Allowance for loan and lease losses	2,126		2,126		2,256
Commercial and Industrial [Member]
Allowance for credit losses, Beginning balance	526	535	433	621
Loans and leases charged-off	(92)	(62)	(155)	(140)
Recoveries of previous charge-offs	4	9	8	13
Provision for credit losses	87	(8)	239	(20)
Allowance for credit losses, Ending balance	525	474	525	474
Allowance for loan and lease losses	525		525		433
Commercial Real Estate - Other [Member]
Allowance for credit losses, Beginning balance	294	497	334	446
Loans and leases charged-off	(51)	(81)	(124)	(149)
Recoveries of previous charge-offs	3	6	6	9
Provision for credit losses	59	40	89	156
Allowance for credit losses, Ending balance	305	462	305	462
Allowance for loan and lease losses	305		305		334
Commercial Real Estate - Residential ADC [Member]
Allowance for credit losses, Beginning balance	206	421	286	469
Loans and leases charged-off	(74)	(78)	(128)	(149)
Recoveries of previous charge-offs	23	7	31	11
Provision for credit losses	2	32	(32)	51
Allowance for credit losses, Ending balance	157	382	157	382
Allowance for loan and lease losses	157		157		286
Commercial Other Lending Subsidiaries [Member]
Allowance for credit losses, Beginning balance	13	18	11	21
Loans and leases charged-off	(3)	(2)	(6)	(4)
Recoveries of previous charge-offs	0	1	1	2
Provision for credit losses	3	(4)	7	(6)
Allowance for credit losses, Ending balance	13	13	13	13
Allowance for loan and lease losses	13		13		11
Direct Retail Lending [Member]
Allowance for credit losses, Beginning balance	301	245	232	246
Loans and leases charged-off	(56)	(66)	(113)	(144)
Recoveries of previous charge-offs	8	8	18	17
Provision for credit losses	30	46	146	114
Allowance for credit losses, Ending balance	283	233	283	233
Allowance for loan and lease losses	283		283		232
Retail Revolving Credit [Member]
Allowance for credit losses, Beginning balance	94	105	112	109
Loans and leases charged-off	(20)	(24)	(42)	(51)
Recoveries of previous charge-offs	4	5	9	10
Provision for credit losses	12	17	11	35
Allowance for credit losses, Ending balance	90	103	90	103
Allowance for loan and lease losses	90		90		112
Retail Residential Mortgage [Member]
Allowance for credit losses, Beginning balance	301	328	365	298
Loans and leases charged-off	(30)	(129)	(72)	(183)
Recoveries of previous charge-offs	1	1	2	2
Provision for credit losses	37	147	14	230
Allowance for credit losses, Ending balance	309	347	309	347
Allowance for loan and lease losses	309		309		365
Retail Sales Finance [Member]
Allowance for credit losses, Beginning balance	32	43	38	47
Loans and leases charged-off	(7)	(7)	(14)	(17)
Recoveries of previous charge-offs	2	3	5	5
Provision for credit losses	(2)	3	(4)	7
Allowance for credit losses, Ending balance	25	42	25	42
Allowance for loan and lease losses	25		25		38
Retail Other Lending Subsidiaries [Member]
Allowance for credit losses, Beginning balance	182	175	186	177
Loans and leases charged-off	(44)	(41)	(101)	(91)
Recoveries of previous charge-offs	7	6	13	11
Provision for credit losses	55	31	102	74
Allowance for credit losses, Ending balance	200	171	200	171
Allowance for loan and lease losses	200		200		186
Covered and Other Acquired [Member]
Allowance for credit losses, Beginning balance	137	144	149	144
Loans and leases charged-off	(12)	0	(27)	0
Recoveries of previous charge-offs	0	0	0	0
Provision for credit losses	14	15	17	15
Allowance for credit losses, Ending balance	139	159	139	159
Allowance for loan and lease losses	139		139		149
Unallocated [Member]
Allowance for credit losses, Beginning balance	95	130	110	130
Loans and leases charged-off	0	0	0	0
Recoveries of previous charge-offs	0	0	0	0
Provision for credit losses	(15)	0	(30)	0
Allowance for credit losses, Ending balance	80	130	80	130
Allowance for loan and lease losses	80		80		110
Allowance for Loan and Lease Losses [Member]
Allowance for credit losses, Beginning balance	2,181	2,641	2,256	2,708
Loans and leases charged-off	(389)	(490)	(782)	(928)
Recoveries of previous charge-offs	52	46	93	80
Provision for credit losses	282	319	559	656
Allowance for credit losses, Ending balance	2,126	2,516	2,126	2,516
Reserve For Unfunded Lending Commitments [Member]
Allowance for credit losses, Beginning balance	40	50	29	47
Loans and leases charged-off	0	0	0	0
Recoveries of previous charge-offs	0	0	0	0
Provision for credit losses	(9)	9	2	12
Allowance for credit losses, Ending balance	31	59	31	59
Allowance for Credit Losses [Member]
Allowance for credit losses, Beginning balance	2,221	2,691	2,285	2,755
Loans and leases charged-off	(389)	(490)	(782)	(928)
Recoveries of previous charge-offs	52	46	93	80
Provision for credit losses	273	328	561	668
Allowance for credit losses, Ending balance	$ 2,157	$ 2,575	$ 2,157	$ 2,575