VACATION OWNERSHIP NOTES RECEIVABLE - Legacy-ILG Vacation Ownership Notes Receivable (Details) - Legacy-ILG - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	$ 137	$ 78
Current	691	789
Total vacation ownership notes receivable	828	867
Non-Securitized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	103	51
Current	85	250
Total vacation ownership notes receivable	188	301
Securitized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	34	27
Current	606	539
Total vacation ownership notes receivable	640	566
31 – 90 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	29	29
31 – 90 days past due | Non-Securitized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	7	11
31 – 90 days past due | Securitized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	22	18
91 – 150 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	10	9
91 – 150 days past due | Non-Securitized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	3	3
91 – 150 days past due | Securitized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	7	6
Greater than 120 days past due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	98	40
Greater than 120 days past due | Non-Securitized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	93	37
Greater than 120 days past due | Securitized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total past due	5	3
Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	$ 430	$ 428