Goodwill and Intangible Assets, Net - Changes in Goodwill by Reportable Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 7,143	$ 7,171
Impairment charges	(297)	0	$ (14)
Foreign exchange translation and other	3	(28)
Goodwill, Ending Balance	6,849	7,143	7,171
B2C
Goodwill [Roll Forward]
Goodwill, Beginning Balance	6,433	6,462
Impairment charges	0
Foreign exchange translation and other	3	(29)
Goodwill, Ending Balance	6,436	6,433	6,462
B2B
Goodwill [Roll Forward]
Goodwill, Beginning Balance	412	394
Impairment charges	0		(14)
Foreign exchange translation and other	1	18
Goodwill, Ending Balance	413	412	394
trivago
Goodwill [Roll Forward]
Goodwill, Beginning Balance	298	315
Impairment charges	(297)
Foreign exchange translation and other	(1)	(17)
Goodwill, Ending Balance	$ 0	$ 298	$ 315