CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock-based compensation	$ 203	$ 149	$ 242
Cost of revenue
Stock-based compensation	11	10	11
Selling and marketing
Stock-based compensation	44	40	47
Technology and content
Stock-based compensation	61	55	63
General and administrative
Stock-based compensation	87	44	108
Restructuring and related reorganization charges
Stock-based compensation	$ 0	$ 0	$ 13