Goodwill and Intangible Assets, Net - Changes in Goodwill by Reportable Segment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 7,380,000,000	$ 8,127,000,000
Impairment charges	(14,000,000)	(799,000,000)	$ 0
Additions	5,000,000
Deductions	(201,000,000)
Foreign exchange translation and other	1,000,000	52,000,000
Goodwill, Ending Balance	7,171,000,000	7,380,000,000	8,127,000,000
Retail
Goodwill [Roll Forward]
Goodwill, Beginning Balance	6,505,000,000	7,049,000,000
Impairment charges	0	(559,000,000)
Additions	0
Deductions	(34,000,000)
Foreign exchange translation and other	(9,000,000)	15,000,000
Goodwill, Ending Balance	6,462,000,000	6,505,000,000	7,049,000,000
B2B
Goodwill [Roll Forward]
Goodwill, Beginning Balance	538,000,000	529,000,000
Impairment charges	(14,000,000)	0
Additions	0
Deductions	(167,000,000)
Foreign exchange translation and other	37,000,000	9,000,000
Goodwill, Ending Balance	394,000,000	538,000,000	529,000,000
trivago
Goodwill [Roll Forward]
Goodwill, Beginning Balance	337,000,000	549,000,000
Impairment charges	0	(240,000,000)
Additions	5,000,000
Deductions	0
Foreign exchange translation and other	(27,000,000)	28,000,000
Goodwill, Ending Balance	$ 315,000,000	$ 337,000,000	$ 549,000,000