Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Revenue		$ 415	$ 354	$ 1,183	$ 958
Costs and expenses:
Cost of revenue	[1]	16	11	46	28
Selling and marketing	[2]	197	159	546	387
Technology and content	[2]	54	46	152	125
General and administrative	[2]	37	36	114	94
Depreciation		13	12	42	33
Amortization of intangible assets		10	6	26	11
Total costs and expenses		327	270	926	678
Operating income		88	84	257	280
Other income (expense):
Interest expense		(3)	(2)	(7)	(6)
Interest income and other, net (Note 16)		13	(7)	15	(7)
Total other income (expense), net		10	(9)	8	(13)
Income before income taxes		98	75	265	267
Provision for income taxes		(24)	(21)	(70)	(77)
Net income		$ 74	$ 54	$ 195	$ 190
Earnings per share attributable to common stockholders (Note 14):
Basic		$ 0.51	$ 0.38	$ 1.35	$ 1.33
Diluted		$ 0.51	$ 0.37	$ 1.34	$ 1.30
Weighted average common shares outstanding (Note 14):
Basic		144,133	142,842	143,662	142,648
Diluted		145,828	146,071	145,886	145,839

[1] Excludes amortization expense as follows:

[2] Includes stock-based compensation expense as follows: