Summary Results of Operations for the One Hotel Sold During the First Quarter of Twenty Seventeen and Ten Hotels Sold in Twenty Sixteen Which are Included in Continuing Operations (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Disposal Group Not Discontinued Operation Disposal Disclosures [Abstract]
Revenues	$ 3	$ 68
Income before taxes and gain on disposal	1	11
Gain on disposals	$ 15	$ 58