Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013 Hotel	Dec. 31, 2012 Hotel	Dec. 31, 2013 Subsequent event [Member]	Mar. 31, 2013 VIEs 21 [Member]	Dec. 31, 2012 VIEs 21 [Member] Hotel	Mar. 31, 2013 VIEs 2 [Member]	Dec. 31, 2012 VIEs 2 [Member] Hotel
Variable Interest Entity [Line Items]
Total number of hotels in which company has variable interest entity	23	23
Investments associated with VIEs				$ 114	$ 109	$ 5	$ 5
Loan Balance with VIEs				2
Number of hotels in which company has an investment	21				21		2
Possible cash outlays under contracts with performance guarantees				62
Loans to owners	3
Unfunded loan commitments expected to be funded in total	0
Unfunded loan commitments	18		18
Equity and other potential contributions associated with managed or joint venture properties	85
Equity and other potential contributions associated with managed or joint venture properties expected to be funded within one year	43
Surety bonds issued	82
Range of possible loss, minimum	0
Range of possible loss, maximum	$ 27