Segment and Geographic Information - Summary of Total Revenue by Product (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue from External Customer [Line Items]
Total revenue	$ 288	$ 354	$ 323	$ 281	$ 213	$ 255	$ 247	$ 230	$ 1,246	$ 945	$ 763
Click-based advertising
Revenue from External Customer [Line Items]
Total revenue									870	696	588
Display-based advertising
Revenue from External Customer [Line Items]
Total revenue									140	119	94
Subscription, transaction and other
Revenue from External Customer [Line Items]
Total revenue									$ 236	$ 130	$ 81