Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Revenue		$ 421	$ 415	$ 1,164	$ 1,183
Costs and expenses:
Cost of revenue	[1]	19	16	55	46
Selling and marketing	[2]	210	197	584	546
Technology and content	[2]	62	54	185	152
General and administrative	[2]	38	37	110	114
Depreciation		18	13	51	42
Amortization of intangible assets		8	10	23	26
Total costs and expenses:		355	327	1,008	926
Operating income		66	88	156	257
Other income (expense):
Interest expense		(3)	(3)	(10)	(7)
Interest income and other, net (Note 14)			13		15
Total other income (expense), net		(3)	10	(10)	8
Income before income taxes		63	98	146	265
Provision for income taxes		(8)	(24)	(27)	(70)
Net income		$ 55	$ 74	$ 119	$ 195
Earnings per share attributable to common stockholders (Note 5):
Basic		$ 0.38	$ 0.51	$ 0.82	$ 1.35
Diluted		$ 0.37	$ 0.51	$ 0.81	$ 1.34
Weighted average common shares outstanding (Note 5):
Basic		145,678	144,133	145,618	143,662
Diluted		147,217	145,828	147,161	145,886

[1] Excludes amortization as follows:

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