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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Variable Interest Entity [Line Items]
Interest income	$ 67	$ 67	$ 136	$ 132
General and Administrative Expense	19	$ 64	89	$ 131
Variable interest entity
Variable Interest Entity [Line Items]
Interest income	64		127
Interest expense to investors	14		29
Debt issuance cost amortization	2		4
General and Administrative Expense			1
Variable interest entity | Vacation Ownership Notes Receivable Securitizations
Variable Interest Entity [Line Items]
Interest income	52		109
Interest expense to investors	12		26
Debt issuance cost amortization	2		3
General and Administrative Expense			1
Variable interest entity | Warehouse Credit Facility
Variable Interest Entity [Line Items]
Interest income	12		18
Interest expense to investors	2		3
Debt issuance cost amortization	$ 0		1
General and Administrative Expense			$ 0