Revenue Recognition (Disaggregation of Net Revenues) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	$ 410	$ 382	$ 1,112	$ 1,095
Capitalized contract cost, net	87		87		$ 84
Balance Sheet Location [Axis]: us-gaap:OtherAssetsCurrent
Disaggregation of Revenue [Line Items]
Capitalized contract cost, net	5		5		5
Balance Sheet Location [Axis]: us-gaap:OtherAssetsNoncurrent
Disaggregation of Revenue [Line Items]
Capitalized contract cost, net	82		82		$ 79
Royalties and franchise fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	156	147	409	420
Marketing and reservation fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	135	128	355	365
Deferred loyalty program revenues
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	23	21	71	66
Management fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	2	2	6	7
License and other fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	36	35	97	95
Other
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	52	49	164	142
Partnership fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	27	24	88	71
Other Products and Services Excluding Partnership Fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	25	25	76	71
Owned Hotel Revenues
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	$ 6	$ 0	$ 10	$ 0