BUSINESS SEGMENTS - Assets (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total assets	$ 9,011	$ 9,214
Operating segments
Segment Reporting Information [Line Items]
Total assets	7,910	8,507
Operating segments | Vacation Ownership
Segment Reporting Information [Line Items]
Total assets	6,936	7,345
Operating segments | Exchange & Third-Party Management
Segment Reporting Information [Line Items]
Total assets	974	1,162
Corporate and Other
Segment Reporting Information [Line Items]
Total assets	$ 1,101	$ 707