Acquisitions and Discontinued Operations - Components of Income (Loss) from Discontinued Operations, Net of Taxes for Education Lending Business (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income	$ 578	$ 572	$ 1,742	$ 1,663
Provision (credit) for loan and lease losses			111
Net interest income (expense) after provision for loan and lease losses	550	463	1,631	1,491
Noninterest income	(459)	(518)	(1,313)	(1,417)
Noninterest expense	716	712	2,108	2,084
Income taxes	59	51	201	178
Income (loss) from discontinued operations, net of taxes	37	3	45	16
Segment, Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income	26	28	80	89
Provision (credit) for loan and lease losses	(6)	2	(10)	(4)
Net interest income (expense) after provision for loan and lease losses	20	30	70	85
Noninterest income	(61)	(5)	(84)	(43)
Noninterest expense	23	31	80	103
Income (loss) before income taxes	58	4	74	25
Income taxes	21	1	29	9
Income (loss) from discontinued operations, net of taxes	37	3	45	16
Education Lending [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) before income taxes	(80)		(78)	17
Income taxes	(30)		(29)	6
Income (loss) from discontinued operations, net of taxes	(50)		(49)	11
Education Lending [Member] | Segment, Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net interest income	26	28	80	89
Provision (credit) for loan and lease losses	6	(2)	10	4
Net interest income (expense) after provision for loan and lease losses	20	30	70	85
Noninterest income	(94)	(21)	(128)	(41)
Noninterest expense	$ 6	$ 9	$ 20	$ 27