Loans and ACL (Analysis of the Allowance for Credit Losses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Provision for credit losses	$ 74	$ 168	$ 134	$ 440
Commercial and Industrial, Excluding Covered [Member]
ACL, beginning balance	423	528	454	470
Charge-offs	(40)	(70)	(73)	(161)
Recoveries	10	10	19	17
Provision for credit losses	30	(9)	23	133
ACL, ending balance	423	459	423	459
CRE Income Producing Properties, Excluding Covered [Member]
ACL, beginning balance	136	151	149	170
Charge-offs	(11)	(24)	(19)	(58)
Recoveries	3	6	5	9
Provision for credit losses	(1)	30	(8)	42
ACL, ending balance	127	163	127	163
CRE Construction And Development, Excluding Covered [Member]
ACL, beginning balance	65	67	76	134
Charge-offs	(3)	(25)	(7)	(47)
Recoveries	10	4	13	11
Provision for credit losses	(13)	61	(23)	9
ACL, ending balance	59	107	59	107
Commercial Other Lending Subsidiaries, Excluding Covered [Member]
ACL, beginning balance	16	13	15	13
Charge-offs	(1)	(1)	(2)	(2)
Recoveries	1	0	1	1
Provision for credit losses	1	4	3	4
ACL, ending balance	17	16	17	16
Direct Retail Lending, Excluding Covered [Member]
ACL, beginning balance	120	254	209	300
Charge-offs	(19)	(42)	(38)	(84)
Recoveries	7	10	15	18
Provision for credit losses	16	(4)	23	(16)
Other			(85)
ACL, ending balance	124	218	124	218
Retail Revolving Credit, Excluding Covered [Member]
ACL, beginning balance	115	97	115	102
Charge-offs	(18)	(20)	(36)	(41)
Recoveries	5	5	10	10
Provision for credit losses	10	31	23	42
ACL, ending balance	112	113	112	113
Retail Residential Mortgage-Nonguaranteed, Excluding Covered [Member]
ACL, beginning balance	327	261	269	296
Charge-offs	(20)	(16)	(41)	(48)
Recoveries	0	1	1	2
Provision for credit losses	17	22	10	18
Other			85
ACL, ending balance	324	268	324	268
Retail Residential Mortgage-Government Guaranteed, Excluding Covered [Member]
ACL, beginning balance	69	55	62	32
Charge-offs	(1)	0	(1)	(1)
Recoveries	0	0	0	0
Provision for credit losses	(17)	6	(10)	30
ACL, ending balance	51	61	51	61
Retail Sales Finance, Excluding Covered [Member]
ACL, beginning balance	45	30	45	29
Charge-offs	(4)	(5)	(11)	(11)
Recoveries	2	2	5	4
Provision for credit losses	1	15	5	20
ACL, ending balance	44	42	44	42
Retail Other Lending Subsidiaries, Excluding Covered [Member]
ACL, beginning balance	222	300	224	264
Charge-offs	(46)	(60)	(130)	(127)
Recoveries	8	10	16	18
Provision for credit losses	34	38	108	133
ACL, ending balance	218	288	218	288
Covered [Member]
ACL, beginning balance	104	139	114	128
Charge-offs	(4)	(2)	(7)	(16)
Recoveries	0	0	0	0
Provision for credit losses	(9)	(11)	(16)	14
ACL, ending balance	91	126	91	126
Unallocated [Member]
ACL, beginning balance		80		80
Charge-offs		0		0
Recoveries		0		0
Provision for credit losses		(40)		(40)
ACL, ending balance		40		40
ALLL [Member]
ACL, beginning balance	1,642	1,975	1,732	2,018
Charge-offs	(167)	(265)	(365)	(596)
Recoveries	46	48	85	90
Provision for credit losses	69	143	138	389
ACL, ending balance	1,590	1,901	1,590	1,901
RUFC [Member]
ACL, beginning balance	80	56	89	30
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision for credit losses	5	25	(4)	51
ACL, ending balance	85	81	85	81
ACL [Member]
ACL, beginning balance	1,722	2,031	1,821	2,048
Charge-offs	(167)	(265)	(365)	(596)
Recoveries	46	48	85	90
Provision for credit losses	74	168	134	440
ACL, ending balance	$ 1,675	$ 1,982	$ 1,675	$ 1,982