BUSINESS SEGMENTS - Revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	$ 1,186	$ 1,252	$ 3,533	$ 3,468
Revenues excluding reimbursed costs	743	881	2,370	2,457
United States
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues excluding reimbursed costs	622	771	2,038	2,173
All other countries
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues excluding reimbursed costs	121	110	332	284
Operating segments
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	1,190	1,253	3,535	3,458
Operating segments | Vacation Ownership
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	1,126	1,182	3,335	3,229
Operating segments | Exchange & Third-Party Management
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	64	71	200	229
Corporate and Other
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	$ (4)	$ (1)	$ (2)	$ 10