Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property Plant And Equipment [Line Items]
Property and equipment, net	$ 260	$ 247
Depreciation of property and equipment, including amortization of internal-use software and website development	69	57	$ 47
Capitalized Software and Website Development
Property Plant And Equipment [Line Items]
Property and equipment, net	86	71
Capitalized computer software and website development costs	62	52
Depreciation of property and equipment, including amortization of internal-use software and website development	46	$ 37	$ 30
Property and equipment, dispositions	$ 45