VARIABLE INTEREST ENTITIES - Interest Income and Expense Recognized as a Result of Our Involvement with Variable Interest Entities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Variable Interest Entity [Line Items]
Interest income	$ 63	$ 69	$ 199	$ 201
General and Administrative Expense	32	$ 57	121	$ 188
Variable interest entity
Variable Interest Entity [Line Items]
Interest income	59		186
Interest expense to investors	15		43
Debt issuance cost amortization	2		6
General and Administrative Expense	1		1
Variable interest entity | Vacation Ownership Notes Receivable Securitizations
Variable Interest Entity [Line Items]
Interest income	59		168
Interest expense to investors	14		39
Debt issuance cost amortization	1		5
General and Administrative Expense	1		1
Variable interest entity | Warehouse Credit Facility
Variable Interest Entity [Line Items]
Interest income	0		18
Interest expense to investors	1		4
Debt issuance cost amortization	1		1
General and Administrative Expense	$ 0		$ 0