BUSINESS SEGMENTS - Revenues (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	$ 1,010	$ 1,034
Vacation Ownership
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	908	905
Exchange & Third-Party Management
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	107	124
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	1,015	1,029
Operating Segments | Vacation Ownership
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	908	905
Operating Segments | Exchange & Third-Party Management
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	107	124
Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	$ (5)	$ 5