Revenue Recognition (Disaggregation of Net Revenues) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	$ 375	$ 397	$ 702	$ 713
Royalties and franchise fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	139	147	253	272
Marketing and reservation fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	122	140	220	238
Deferred loyalty program revenues
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	23	25	47	43
Management fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	2	2	5	5
License and other fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	32	33	62	60
Other
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	54	50	111	95
Partnership fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	28	24	62	47
Other Products and Services Excluding Partnership Fees
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	26	26	49	48
Owned Hotel Revenues
Disaggregation of Revenue [Line Items]
Royalties and franchise fee revenues	$ 3	$ 0	$ 4	$ 0