Business Segments - Schedule of Business Segments (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net interest income	$ 4,553		$ 4,001	$ 9,123	$ 7,415
Non-interest income	1,085		1,054	2,066	2,575
Total net revenue	5,638		5,055	11,189	9,990
Provision for credit losses	762	37	1,677	1,647	2,250
PCCR intangible amortization	110		88	226	92
Core deposit intangible amortization	43		51	87	97
Total PCCR and core deposit intangible amortization	153		139	313	189
Other non-interest expense	2,906		3,003	5,774	5,457
Total non-interest expense	3,059		3,142	6,087	5,646
Income from continuing operations before income taxes	1,817		236	3,455	2,094
Income tax provision (benefit)	581		43	1,075	396
Income from continuing operations, net of tax	1,236		193	2,380	1,698
Total loans held for investment	191,512			191,512		205,889
Total customer deposits	209,865			209,865		212,485
Credit Card [Member]
Segment Reporting Information [Line Items]
Net interest income	2,804		2,350	5,634	4,342
Non-interest income	832		771	1,653	1,369
Total net revenue	3,636		3,121	7,287	5,711
Provision for credit losses	713		1,711	1,456	2,169
PCCR intangible amortization	110		88	226	92
Core deposit intangible amortization	0		0	0	0
Total PCCR and core deposit intangible amortization	110		88	226	92
Other non-interest expense	1,709		1,775	3,441	3,039
Total non-interest expense	1,819		1,863	3,667	3,131
Income from continuing operations before income taxes	1,104		(453)	2,164	411
Income tax provision (benefit)	385		(156)	759	142
Income from continuing operations, net of tax	719		(297)	1,405	269
Total loans held for investment	78,310			78,310		91,755
Total customer deposits	0			0		0
Consumer Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	1,478		1,496	2,956	2,784
Non-interest income	189		185	370	361
Total net revenue	1,667		1,681	3,326	3,145
Provision for credit losses	67		44	242	218
PCCR intangible amortization	0		0	0	0
Core deposit intangible amortization	35		42	72	79
Total PCCR and core deposit intangible amortization	35		42	72	79
Other non-interest expense	875		917	1,728	1,823
Total non-interest expense	910		959	1,800	1,902
Income from continuing operations before income taxes	690		678	1,284	1,025
Income tax provision (benefit)	246		240	457	363
Income from continuing operations, net of tax	444		438	827	662
Total loans held for investment	72,218			72,218		75,127
Total customer deposits	169,789			169,789		172,396
Commercial Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	457		427	911	858
Non-interest income	93		82	177	167
Total net revenue	550		509	1,088	1,025
Provision for credit losses	(14)		(94)	(49)	(163)
PCCR intangible amortization	0		0	0	0
Core deposit intangible amortization	8		9	15	18
Total PCCR and core deposit intangible amortization	8		9	15	18
Other non-interest expense	261		242	512	494
Total non-interest expense	269		251	527	512
Income from continuing operations before income taxes	295		352	610	676
Income tax provision (benefit)	105		124	217	238
Income from continuing operations, net of tax	190		228	393	438
Total loans held for investment	40,805			40,805		38,820
Total customer deposits	30,869			30,869		29,866
Other [Member]
Segment Reporting Information [Line Items]
Net interest income	(186)		(272)	(378)	(569)
Non-interest income	(29)		16	(134)	678
Total net revenue	(215)		(256)	(512)	109
Provision for credit losses	(4)		16	(2)	26
PCCR intangible amortization	0		0	0	0
Core deposit intangible amortization	0		0	0	0
Total PCCR and core deposit intangible amortization	0		0	0	0
Other non-interest expense	61		69	93	101
Total non-interest expense	61		69	93	101
Income from continuing operations before income taxes	(272)		(341)	(603)	(18)
Income tax provision (benefit)	(155)		(165)	(358)	(347)
Income from continuing operations, net of tax	(117)		(176)	(245)	329
Total loans held for investment	179			179		187
Total customer deposits	$ 9,207			$ 9,207		$ 10,223