Discontinued Operations - Results of Discontinued Operations (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Income from discontinued operations before income tax	$ 0		$ 241
Credit Card Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net interest income and other revenues	0	[1]	412	[1]
Income from discontinued operations before income tax	$ 0		$ 241

[1] Interest expense in 2012 was allocated to discontinued operations in accordance with our existing internal transfer pricing policy. This policy uses match funding based on the expected lives of the assets and liabilities of the business at the time of origination, subject to periodic review, as demonstrated by the expected cash flows and re-pricing characteristics of the underlying assets.