Geographical Information - Property and Equipment (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Long-Lived Assets, by Geographical Area
Property and equipment, net	$ 2,391		$ 1,475
United States
Long-Lived Assets, by Geographical Area
Property and equipment, net	2,110		1,444
Rest of world
Long-Lived Assets, by Geographical Area
Property and equipment, net	$ 281	[1]	$ 31	[1]

[1] No individual country exceeded 10% of our total property and equipment, net for any period presented.