Asset Dispositions and Impairments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012 Hotel	Sep. 30, 2011	Sep. 30, 2012 Hotel	Sep. 30, 2011 Hotel
Impaired Long-Lived Assets Held and Used [Line Items]
Net cash proceeds from disposal of wholly-owned hotel	$ 244			$ 237
Number of wholly owned hotels sold	2
Deferred gains on dispositions of assets	100	30	100	30
Net cash proceeds from disposal of wholly-owned hotel			11
Gain on acquisition of business	1	45	(7)	14
Number of wholly owned hotels sold			1	2
Gain on asset dispositions		48
Losses relating to the impairment of an investment		3
Gain on sale of hotel				66
Proceeds from Divestiture of Interest in Joint Venture				44
Company's debt assumed by buyer in sale of interest in consolidated joint venture				57
Loss recognized in discontinued operations from sale of interest in a consolidated joint venture, net of tax		1		19
Approximate proceeds from sale of non-core assets				2
Approximate amount of gain from sale of non-core assets				2
Minority Investment - Japan Hotel [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment loss relating to minority investment in a joint venture hotel located in Japan				$ 32