Segment and Geographic Information - Summary of Segment Information (Parenthetical) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
General and administrative	[1]		$ 177	$ 157	$ 143
Transition tax		$ 67		67
Income tax expense recorded due to remeasurement of net deferred tax assets			2	6
Operating Segments | Hotel Segment
Segment Reporting Information [Line Items]
General and administrative			77	81	80
Operating Segments | Non-Hotel Segment
Segment Reporting Information [Line Items]
General and administrative			$ 50	$ 42	$ 38

[1] Includes stock-based compensation expense as follows