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
	Mar. 31, 2020	Mar. 31, 2019
Variable Interest Entity [Line Items]
Interest income	$ 69	$ 65
Variable Interest Entity
Variable Interest Entity [Line Items]
Interest income	63
Interest expense to investors	14
Debt issuance cost amortization	2
Variable Interest Entity | Vacation Ownership Notes Receivable Securitizations
Variable Interest Entity [Line Items]
Interest income	57
Interest expense to investors	13
Debt issuance cost amortization	2
Variable Interest Entity | Warehouse Credit Facility
Variable Interest Entity [Line Items]
Interest income	6
Interest expense to investors	1
Debt issuance cost amortization	$ 0