Segment Information - Summary of Segment Information (Parenthetical) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
General and administrative	[1]	$ 42	$ 35
Operating Segments | Hotel Segment
Segment Reporting Information [Line Items]
General and administrative		20	19
Operating Segments | Non-Hotel Segment
Segment Reporting Information [Line Items]
General and administrative		$ 12	$ 9

[1] Includes stock-based compensation expense as follows