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, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Provision for credit losses	$ 34	$ 92	$ 168	$ 532
Commercial and Industrial, Excluding Covered [Member]
ACL, beginning balance	423	459	454	470
Charge-offs	(31)	(42)	(104)	(203)
Recoveries	10	17	29	34
Provision for credit losses	(5)	36	18	169
ACL, ending balance	397	470	397	470
CRE Income Producing Properties, Excluding Covered [Member]
ACL, beginning balance	127	163	149	170
Charge-offs	(8)	(10)	(27)	(69)
Recoveries	2	7	7	15
Provision for credit losses	53	(11)	45	33
ACL, ending balance	174	149	174	149
CRE Construction And Development, Excluding Covered [Member]
ACL, beginning balance	59	107	76	134
Charge-offs	(2)	(7)	(9)	(53)
Recoveries	2	11	15	23
Provision for credit losses	(9)	(32)	(32)	(25)
ACL, ending balance	50	79	50	79
Commercial Other Lending Subsidiaries, Excluding Covered [Member]
ACL, beginning balance	17	16	15	13
Charge-offs	(4)	(1)	(8)	(3)
Recoveries	1	0	2	1
Provision for credit losses	8	2	13	6
ACL, ending balance	22	17	22	17
Direct Retail Lending, Excluding Covered [Member]
ACL, beginning balance	124	218	209	300
Charge-offs	(17)	(35)	(55)	(119)
Recoveries	7	11	22	29
Provision for credit losses	6	17	29	1
Other			(85)
ACL, ending balance	120	211	120	211
Retail Revolving Credit, Excluding Covered [Member]
ACL, beginning balance	112	113	115	102
Charge-offs	(17)	(22)	(53)	(63)
Recoveries	4	3	14	13
Provision for credit losses	9	22	32	64
ACL, ending balance	108	116	108	116
Retail Residential Mortgage-Nonguaranteed, Excluding Covered [Member]
ACL, beginning balance	324	268	269	296
Charge-offs	(31)	(15)	(72)	(63)
Recoveries	1	0	2	2
Provision for credit losses	(41)	(17)	(31)	1
Other			85
ACL, ending balance	253	236	253	236
Retail Residential Mortgage-Government Guaranteed, Excluding Covered [Member]
ACL, beginning balance	51	61	62	32
Charge-offs	(1)	0	(2)	(1)
Recoveries	0	0	0	0
Provision for credit losses	(9)	(8)	(19)	22
ACL, ending balance	41	53	41	53
Retail Sales Finance, Excluding Covered [Member]
ACL, beginning balance	44	42	45	29
Charge-offs	(5)	(5)	(16)	(16)
Recoveries	2	3	7	7
Provision for credit losses	6	3	11	23
ACL, ending balance	47	43	47	43
Retail Other Lending Subsidiaries, Excluding Covered [Member]
ACL, beginning balance	218	288	224	264
Charge-offs	(62)	(65)	(190)	(192)
Recoveries	7	8	23	26
Provision for credit losses	50	61	156	194
ACL, ending balance	213	292	213	292
Covered [Member]
ACL, beginning balance	91	126	114	128
Charge-offs	0	(2)	(7)	(18)
Recoveries	0	0	0	0
Provision for credit losses	(12)	2	(28)	16
ACL, ending balance	79	126	79	126
Unallocated [Member]
ACL, beginning balance		40		80
Charge-offs		0		0
Recoveries		0		0
Provision for credit losses		6		(34)
ACL, ending balance		46		46
ALLL [Member]
ACL, beginning balance	1,590	1,901	1,732	2,018
Charge-offs	(178)	(204)	(543)	(800)
Recoveries	36	60	121	150
Provision for credit losses	56	81	194	470
ACL, ending balance	1,504	1,838	1,504	1,838
RUFC [Member]
ACL, beginning balance	85	81	89	30
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for credit losses	(22)	11	(26)	62
ACL, ending balance	63	92	63	92
ACL [Member]
ACL, beginning balance	1,675	1,982	1,821	2,048
Charge-offs	(178)	(204)	(543)	(800)
Recoveries	36	60	121	150
Provision for credit losses	34	92	168	532
ACL, ending balance	$ 1,567	$ 1,930	$ 1,567	$ 1,930