Discontinued Operations - Summary of Assets and Liabilities of Disposal Group Held for Sale (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	$ 174	$ 103	$ 72	$ 11
Assets of discontinued operations	2,085	12,901
Liabilities of discontinued operations	1,521	2,569
Insurance business [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	2	5
Interest bearing deposit with bank	32	3
Available-for-sale securities	1,474	1,851
Other assets	247	143
Assets of discontinued operations	1,755	2,002
Insurance policy and claim reserves	996	1,049
Other liabilities	175	43
Liabilities of discontinued operations	1,171	1,092
Card and Retail Services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash	172	96
Receivables		9,001
Intangible assets		514
Properties and equipment, net		95
Other assets	84	1,102
Assets of discontinued operations	256	10,808
Long-term debt		211
Other liabilities	349	1,257
Liabilities of discontinued operations	$ 349	$ 1,468