BUSINESS SEGMENTS - Revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	$ 480	$ 1,043	$ 1,490	$ 2,077
Vacation Ownership
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	405	924	1,313	1,829
Exchange & Third-Party Management
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	58	116	165	240
Operating segments
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	463	1,040	1,478	2,069
Operating segments | Vacation Ownership
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	405	924	1,313	1,829
Operating segments | Exchange & Third-Party Management
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	58	116	165	240
Corporate and Other
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	$ 17	$ 3	$ 12	$ 8