Significant Accounting Policies - Additional Information (Details) $ in Millions		12 Months Ended
		Dec. 31, 2020 USD ($) Subsidiary	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jan. 01, 2020 USD ($)	Dec. 31, 2017 USD ($)
Schedule Of Accounting Policies [Line Items]
Advertising expense		$ 118	$ 423	$ 544
Expected dividend yield		0.00%
Financial instruments including money market funds maturities period		90 days
Minimum maturities of short-term marketable securities		90 days
Maximum remaining maturity for short-term marketable securities		12 months
Maximum maturity period for marketable security		3 years
Weighted Average Maturity		18 months
Customer invoices due period		30 days
Minimum probability that the fair value of the reporting unit is less than the carrying amount		50.00%
Deferred merchant payables		$ 36	159
Minimum maturity at purchase date for a short term marketable security		90 days
Net foreign currency exchange gains/(losses)	[1]	$ 5	(2)	(9)
Foreign currency exchange contracts maturity period, maximum		90 days
Retained earnings		$ 389	681
Available for sale securities		0	0
U.S. Treasury Securities
Schedule Of Accounting Policies [Line Items]
Portfolio based securities loss expectation		0
U.S. Government Agency Securities
Schedule Of Accounting Policies [Line Items]
Portfolio based securities loss expectation		$ 0
Cumulative Effect, Period of Adoption, Adjustment | Revision of Prior Period, Adjustment
Schedule Of Accounting Policies [Line Items]
Retained earnings			$ (3)	$ (1)	$ (3)	$ 4
Customer Concentration Risk | Sales | Expedia
Schedule Of Accounting Policies [Line Items]
Customer concentration risk		10.00%	10.00%	10.00%
Customer Concentration Risk | Sales | Booking
Schedule Of Accounting Policies [Line Items]
Customer concentration risk		10.00%	10.00%	10.00%
Customer Concentration Risk | Sales | Expedia and Booking
Schedule Of Accounting Policies [Line Items]
Customer concentration risk		25.00%	33.00%	37.00%
Minimum
Schedule Of Accounting Policies [Line Items]
Depreciation over the estimated useful lives of assets		3 years
Maximum
Schedule Of Accounting Policies [Line Items]
Depreciation over the estimated useful lives of assets		5 years
Stock Options
Schedule Of Accounting Policies [Line Items]
Term of stock options, granted		10 years
Stock options vest period		4 years
Restricted Stock Units
Schedule Of Accounting Policies [Line Items]
Stock options vest period		4 years
China
Schedule Of Accounting Policies [Line Items]
Number of operating subsidiaries | Subsidiary		1

[1] Our foreign currency exchange gains (losses), net, are generally related to foreign exchange transaction gains and losses from the conversion of the transaction currency to the functional currency, partially offset by the forward contract gains and losses.