Acquisitions - Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016 USD ($) Business	Sep. 30, 2015 USD ($)
Business Acquisition [Line Items]
Cash consideration paid, net of cash acquired	$ 23	$ 29
Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Number of business acquired | Business	3
Total acquisition purchase price	$ 27
Cash consideration paid, net of cash acquired	22
Cash acquired from acquisition	3
Cash held back on acquisition	2
Acquisition-related costs	$ 1
Tous Au Restaurant
Business Acquisition [Line Items]
Business acquisition percentage of outstanding shares of capital stock	100.00%
Date of acquisition	Jan. 31, 2016
HouseTrip
Business Acquisition [Line Items]
Business acquisition percentage of outstanding shares of capital stock	100.00%
Date of acquisition	Apr. 30, 2016
CityMaps
Business Acquisition [Line Items]
Business acquisition percentage of outstanding shares of capital stock	100.00%
Date of acquisition	Aug. 30, 2016