Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Costs and expenses:
Amortization of intangible assets	$ 10	$ 6	$ 26	$ 11
Depreciation	13	12	42	33
Amortization adjustment	10	9	34	23
Stock-based compensation:
Stock-based compensation	19	17	52	46
Selling and Marketing
Stock-based compensation:
Stock-based compensation	4	4	12	10
Technology and Content
Stock-based compensation:
Stock-based compensation	8	7	20	19
General and Administrative
Stock-based compensation:
Stock-based compensation	7	6	20	17
Acquired technology
Costs and expenses:
Amortization of intangible assets	2	1	7	2
Website development costs
Costs and expenses:
Depreciation	$ 8	$ 8	$ 27	$ 21