BUSINESS SEGMENTS - Adjusted EBITDA (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Corporate and other	$ (24)	$ (50)	$ (84)	$ (164)
Interest expense	(37)	(31)	(112)	(100)
Tax benefit (provision)	14	(10)	91	(50)
Depreciation and amortization	(30)	(33)	(93)	(106)
Share-based compensation expense	(11)	(9)	(24)	(29)
Certain items	(33)	(116)	(263)	(202)
NET (LOSS) INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	(62)	(9)	(238)	64
Vacation Ownership
Segment Reporting Information [Line Items]
Adjusted earnings before income taxes depreciation and amortization	28	195	156	570
Exchange & Third-Party Management
Segment Reporting Information [Line Items]
Adjusted earnings before income taxes depreciation and amortization	$ 31	$ 45	$ 91	$ 145