Discontinued Operations - Results of Discontinued Operations (Parenthetical) (Detail) (Credit Card Receivable [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2012	Dec. 31, 2011
Credit Card Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost or fair value adjustment	$ 440	$ 1,000	$ 604