Other Liabilities - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2009
Cash received toward the purchase of SPG points by American Express			$ 250
Financial arrangement with an implicit interest rate			4.50%
Fixed amount per year to be deducted from advance as a part of amendment	50
Period for deduction of financing arrangement	5 years
Other liabilities related to amendment	$ 28	$ 72