Discontinued Operations - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended			6 Months Ended	9 Months Ended			3 Months Ended				9 Months Ended						1 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Sep. 30, 2012 Infrastructure [Member]	Sep. 30, 2012 Insurance business [Member]	Sep. 30, 2011 Insurance business [Member]	Jun. 30, 2012 Insurance business [Member]	Sep. 30, 2012 Insurance business [Member]	Sep. 30, 2011 Insurance business [Member]	Dec. 31, 2011 Insurance business [Member]	Sep. 30, 2012 Card and Retail Services [Member]	Jun. 30, 2012 Card and Retail Services [Member]	Mar. 31, 2012 Card and Retail Services [Member]	Sep. 30, 2011 Card and Retail Services [Member]	Sep. 30, 2012 Card and Retail Services [Member]	Sep. 30, 2011 Card and Retail Services [Member]	May 01, 2012 Card and Retail Services [Member]	Dec. 31, 2011 Card and Retail Services [Member]	Dec. 31, 2011 Card and Retail Services [Member] Revolving Credit Facility [Member]	Dec. 31, 2011 Card and Retail Services [Member] Line of Credit [Member]	Aug. 31, 2010 Auto Finance [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment loss									$ 92,000,000	$ 33,000,000
Sale of insurance operation							181,000,000			181,000,000
Impairment loss after tax										59,000,000
Additional sale proceeds taxable									72,000,000
Available-for-sale securities							1,474,000,000			1,474,000,000		1,851,000,000
Insurance policy and claim reserves							996,000,000			996,000,000		1,049,000,000
Sold business, premium percentage of receivables																			8.75%
Proceeds from divestiture of businesses														11,800,000,000
Pre-tax gain														2,200,000,000
Net cash amount after-tax gain														1,400,000,000
Net interest income and other revenues	(14,000,000)						105,000,000	94,000,000		169,000,000	276,000,000		(14,000,000)			959,000,000	3,342,000,000	2,785,000,000
Loss from discontinued operations before income tax	(36,000,000)	378,000,000	2,685,000,000	885,000,000			28,000,000	5,000,000		(72,000,000)	21,000,000		(64,000,000)			373,000,000	2,737,000,000	870,000,000
Infrastructure related expenses						50,000,000
Net intangible assets related to account relationships purchased																				29,000,000
Gain on sale of intangible assets															79,000,000
Total amounts on secured financings of credit card receivables																					650,000,000
Secured financings balance	5,000,000,000		5,000,000,000		5,300,000,000															195,000,000
Credit card receivables																				355,000,000
Open consumer lines of credit																						105,000,000,000
Outstanding principal balance																							2,600,000,000
Aggregate sales price of assets																							2,500,000,000
Transfer of secured indebtedness																							431,000,000
Net cash proceeds from sale of business																							$ 2,100,000,000