VACATION OWNERSHIP NOTES RECEIVABLE - Legacy-ILG Vacation Ownership Notes Receivable, Brand and FICO score (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	$ 398	$ 439
Acquired | Westin
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	158	177
Acquired | Sheraton
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	211	230
Acquired | Hyatt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	24	26
Acquired | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	5	6
Acquired | 700 +
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	193	216
Acquired | 700 + | Westin
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	91	103
Acquired | 700 + | Sheraton
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	87	95
Acquired | 700 + | Hyatt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	13	15
Acquired | 700 + | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	2	3
Acquired | 600 - 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	139	151
Acquired | 600 - 699 | Westin
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	52	57
Acquired | 600 - 699 | Sheraton
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	77	83
Acquired | 600 - 699 | Hyatt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	9	10
Acquired | 600 - 699 | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	1	1
Acquired | (less than) 600
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	19	20
Acquired | (less than) 600 | Westin
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	4	4
Acquired | (less than) 600 | Sheraton
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	14	15
Acquired | (less than) 600 | Hyatt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	1	1
Acquired | (less than) 600 | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	0	0
Acquired | No Score
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	47	52
Acquired | No Score | Westin
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	11	13
Acquired | No Score | Sheraton
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	33	37
Acquired | No Score | Hyatt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	1	0
Acquired | No Score | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	2	2
Legacy-ILG
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	828	867
Legacy-ILG | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	430	428
Legacy-ILG | Originated | Westin
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	180	198
Legacy-ILG | Originated | Sheraton
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	227	208
Legacy-ILG | Originated | Hyatt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	23	22
Legacy-ILG | Originated | 700 +
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	221	235
Legacy-ILG | Originated | 700 + | Westin
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	105	122
Legacy-ILG | Originated | 700 + | Sheraton
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	101	97
Legacy-ILG | Originated | 700 + | Hyatt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	15	16
Legacy-ILG | Originated | 600 - 699
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	127	113
Legacy-ILG | Originated | 600 - 699 | Westin
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	51	46
Legacy-ILG | Originated | 600 - 699 | Sheraton
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	69	61
Legacy-ILG | Originated | 600 - 699 | Hyatt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	7	6
Legacy-ILG | Originated | (less than) 600
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	22	18
Legacy-ILG | Originated | (less than) 600 | Westin
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	5	5
Legacy-ILG | Originated | (less than) 600 | Sheraton
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	16	13
Legacy-ILG | Originated | (less than) 600 | Hyatt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	1	0
Legacy-ILG | Originated | No Score
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	60	62
Legacy-ILG | Originated | No Score | Westin
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	19	25
Legacy-ILG | Originated | No Score | Sheraton
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	41	37
Legacy-ILG | Originated | No Score | Hyatt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total vacation ownership notes receivable	$ 0	$ 0