Goodwill and Intangible Assets, Net - Changes in Goodwill by Reportable Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 6,849	$ 7,143
Impairment charges	0	(297)	$ 0
Foreign exchange translation and other	(5)	3
Goodwill, Ending Balance	6,844	6,849	7,143
B2C
Goodwill [Roll Forward]
Goodwill, Beginning Balance	6,436	6,433
Impairment charges		0
Foreign exchange translation and other	(3)	3
Goodwill, Ending Balance	6,433	6,436	6,433
B2B
Goodwill [Roll Forward]
Goodwill, Beginning Balance	413	412
Impairment charges		0
Foreign exchange translation and other	(2)	1
Goodwill, Ending Balance	411	413	412
trivago
Goodwill [Roll Forward]
Goodwill, Beginning Balance	0	298
Impairment charges		(297)
Foreign exchange translation and other	0	(1)
Goodwill, Ending Balance	$ 0	$ 0	$ 298