Loans and ACL (Analysis of the Allowance for Credit Losses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Provision for credit losses	$ 92	$ 244	$ 532	$ 805
Commercial and Industrial, Excluding Covered [Member]
ACL, Beginning balance	459	525	470	433
Loans and leases charged-off	(42)	(84)	(203)	(239)
Recoveries of previous charge-offs	17	4	34	12
Provision for credit losses	36	96	169	335
ACL, Ending balance	470	541	470	541
CRE - Other, Excluding Covered [Member]
ACL, Beginning balance	202	305	204	334
Loans and leases charged-off	(11)	(40)	(77)	(164)
Recoveries of previous charge-offs	10	3	21	9
Provision for credit losses	(20)	(30)	33	59
ACL, Ending balance	181	238	181	238
CRE - Residential ADC, Excluding Covered [Member]
ACL, Beginning balance	68	157	100	286
Loans and leases charged-off	(6)	(35)	(45)	(163)
Recoveries of previous charge-offs	8	2	17	33
Provision for credit losses	(23)	(23)	(25)	(55)
ACL, Ending balance	47	101	47	101
Commercial Other Lending Subsidiaries, Excluding Covered [Member]
ACL, Beginning balance	16	13	13	11
Loans and leases charged-off	(1)	(1)	(3)	(7)
Recoveries of previous charge-offs	0	1	1	2
Provision for credit losses	2	1	6	8
ACL, Ending balance	17	14	17	14
Direct Retail Lending, Excluding Covered [Member]
ACL, Beginning balance	218	283	300	232
Loans and leases charged-off	(35)	(57)	(119)	(170)
Recoveries of previous charge-offs	11	9	29	27
Provision for credit losses	17	46	1	192
ACL, Ending balance	211	281	211	281
Retail Revolving Credit, Excluding Covered [Member]
ACL, Beginning balance	113	90	102	112
Loans and leases charged-off	(22)	(20)	(63)	(62)
Recoveries of previous charge-offs	3	5	13	14
Provision for credit losses	22	24	64	35
ACL, Ending balance	116	99	116	99
Retail Residential Mortgage, Excluding Covered [Member]
ACL, Beginning balance	329	309	328	365
Loans and leases charged-off	(15)	(35)	(64)	(107)
Recoveries of previous charge-offs	0	0	2	2
Provision for credit losses	(25)	25	23	39
ACL, Ending balance	289	299	289	299
Retail Sales Finance, Excluding Covered [Member]
ACL, Beginning balance	42	25	29	38
Loans and leases charged-off	(5)	(5)	(16)	(19)
Recoveries of previous charge-offs	3	2	7	7
Provision for credit losses	3	6	23	2
ACL, Ending balance	43	28	43	28
Retail Other Lending Subsidiaries, Excluding Covered [Member]
ACL, Beginning balance	288	200	264	186
Loans and leases charged-off	(65)	(57)	(192)	(158)
Recoveries of previous charge-offs	8	5	26	18
Provision for credit losses	61	85	194	187
ACL, Ending balance	292	233	292	233
Covered [Member]
ACL, Beginning balance	126	139	128	149
Loans and leases charged-off	(2)	(2)	(18)	(29)
Recoveries of previous charge-offs	0	0	0	0
Provision for credit losses	2	0	16	17
ACL, Ending balance	126	137	126	137
Unallocated [Member]
ACL, Beginning balance	40	80	80	110
Loans and leases charged-off	0	0	0	0
Recoveries of previous charge-offs	0	0	0	0
Provision for credit losses	6	0	(34)	(30)
ACL, Ending balance	46	80	46	80
ALLL [Member]
ACL, Beginning balance	1,901	2,126	2,018	2,256
Loans and leases charged-off	(204)	(336)	(800)	(1,118)
Recoveries of previous charge-offs	60	31	150	124
Provision for credit losses	81	230	470	789
ACL, Ending balance	1,838	2,051	1,838	2,051
RUFC [Member]
ACL, Beginning balance	81	31	30	29
Loans and leases charged-off	0	0	0	0
Recoveries of previous charge-offs	0	0	0	0
Provision for credit losses	11	14	62	16
ACL, Ending balance	92	45	92	45
ACL [Member]
ACL, Beginning balance	1,982	2,157	2,048	2,285
Loans and leases charged-off	(204)	(336)	(800)	(1,118)
Recoveries of previous charge-offs	60	31	150	124
Provision for credit losses	92	244	532	805
ACL, Ending balance	$ 1,930	$ 2,096	$ 1,930	$ 2,096