Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenue (Note 3)	[1]	$ 428	$ 458	$ 1,225	$ 1,269
Costs and expenses:
Cost of revenue	[2]	25	23	73	67
Selling and marketing	[3]	176	206	534	621
Technology and content	[3]	76	72	224	207
General and administrative	[3]	51	40	138	129
Depreciation		23	20	69	61
Amortization of intangible assets		9	8	23	24
Total costs and expenses		360	369	1,061	1,109
Operating income		68	89	164	160
Other income (expense):
Interest expense		(2)	(4)	(5)	(10)
Interest income and other, net		7	2	14
Total other income (expense), net		5	(2)	9	(10)
Income before income taxes		73	87	173	150
Provision for income taxes		(23)	(18)	(63)	(45)
Net income		$ 50	$ 69	$ 110	$ 105
Earnings per share attributable to common stockholders (Note 4):
Basic		$ 0.36	$ 0.50	$ 0.79	$ 0.76
Diluted		$ 0.36	$ 0.49	$ 0.78	$ 0.75
Weighted average common shares outstanding (Note 4):
Basic		139,324	137,574	138,937	138,239
Diluted		140,381	140,513	140,818	140,151

[1] Our revenue is recognized primarily at a point in time for all reported segments.

[2] Excludes amortization as follows:

[3] Includes stock-based compensation expense as follows