Geographical Information - Revenue (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Revenue by Geographical Area
Revenue	$ 3,203		$ 2,016		$ 8,615		$ 5,286
United States
Revenue by Geographical Area
Revenue	1,468		940		3,857		2,438
Rest of the World
Revenue by Geographical Area
Revenue	$ 1,735	[1]	$ 1,076	[1]	$ 4,758	[1]	$ 2,848	[1]

[1] No individual country exceeded 10% of our total revenue for any period presented