Discontinued Operations - Results of Discontinued Operations (Parenthetical) (Detail) (Credit Card Receivables [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Credit Card Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost or fair value adjustment	$ 159	$ 440	$ 159