Segment Information - Summary of Segment Information (Parenthetical) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Segment Reporting Information [Line Items]
General and administrative expenses	$ 33	[1]	$ 26	[1]
Operating Segments | Hotel
Segment Reporting Information [Line Items]
General and administrative expenses	20		19
Operating Segments | Other Segment
Segment Reporting Information [Line Items]
General and administrative expenses	$ 6		$ 3

[1] Includes stock-based compensation expense as follows: