Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Allowance for doubtful accounts	$ 6	$ 6
Property and equipment, accumulated depreciation	120	88
Intangible assets, accumulated amortization	$ 68	$ 52
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	1,600,000,000	1,600,000,000
Common stock, shares issued	134,430,268	133,836,242
Common stock, shares outstanding	132,829,000	132,443,111
Treasury stock, shares	1,601,268	1,393,131
Class B Common Stock
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	400,000,000	400,000,000
Common stock, shares issued	12,799,999	12,799,999
Common stock, shares outstanding	12,799,999	12,799,999