Related Party Transactions (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended
	May 01, 2024	Nov. 30, 2021	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Mar. 31, 2025	Dec. 31, 2024
Related Party Transactions
Total revenue			$ 674	$ 597	$ 1,926	$ 1,832
Accounts payable			556		556			$ 263
Accounts receivable (net of allowance for credit losses of $11 and $10 as of September 30, 2025 and December 31, 2024, respectively)			930		930			571
Class A common stock
Related Party Transactions
Loan to equity affiliate					1
Affiliate
Related Party Transactions
Dividends receivable			2		2
Commercial Agreements | Affiliate
Related Party Transactions
Advisory services fees			10	9	30	28
Total revenue			3	2	6	6
Accounts payable			30		30			12
Accounts receivable (net of allowance for credit losses of $11 and $10 as of September 30, 2025 and December 31, 2024, respectively)			3		3			2
Commercial and Operating Agreements with Expedia | Affiliate
Related Party Transactions
Total revenue			44	40	134	138
Accounts receivable (net of allowance for credit losses of $11 and $10 as of September 30, 2025 and December 31, 2024, respectively)			48		48			44
Term of agreement		10 years
Transition Services Agreement with Expedia, Inc | Affiliate
Related Party Transactions
Advisory services fees			1	$ 3	2	$ 12
Accounts payable			$ 0		$ 0			3
Optional services, term	18 months
Payable remaining in respect of loss contingency								$ 7
Payable remaining in respect of loss contingency, paid							$ 3
Payable remaining in respect of loss contingency, payable							$ 4