Fair Value Measurements - Additional Information (Details) - USD ($)		3 Months Ended	12 Months Ended
	Oct. 01, 2018	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (Loss) on investments			$ 8,000,000	$ (111,000,000)	$ (14,000,000)
Net gains(losses) from foreign currency forward contracts			(8,000,000)	47,000,000	17,000,000
Impairment of goodwill			0	86,000,000	0
Investments without readily determinable fair values			467,000,000	476,000,000	0
Cost upward method investments			33,000,000
Cost downward method investments			2,000,000
Foreign currency forward contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amount of foreign currency derivatives			3,200,000,000
Recurring Basis | Foreign currency forward contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency forward contracts			8,000,000
Prepaid expenses				22,000,000
Nonrecurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finite-lived intangible assets, fair value disclosure				27,000,000
Equity securities, gain (loss)			(2,000,000)	33,000,000	(14,000,000)
Equity securities, other-than-temporary impairments					6,000,000
Loss on sale of cost method Investments					9,000,000
Despegar.com Corp.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gain (Loss) on investments			$ 10,000,000	(145,000,000)
Despegar.com Corp. | Available-for-sale Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost					273,000,000
Accumulated gross unrealized loss					$ 9,000,000
Reporting Unit Within Core Online Travel Companies | Nonrecurring Basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of goodwill	$ 25,000,000	$ 61,000,000		86,000,000
Impairment of indefinite-lived intangible assets				$ 42,000,000