FINANCIAL INSTRUMENTS - Carrying Values and Estimated Fair Values - Non-securitized Notes Receivable (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vacation ownership notes receivable	$ 1,913	$ 2,233
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vacation ownership notes receivable	1,951	2,264
Securitized Vacation Ownership Notes Receivable | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vacation ownership notes receivable	1,650	1,750
Securitized Vacation Ownership Notes Receivable | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vacation ownership notes receivable	1,684	1,771
Non-Securitized | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vacation ownership notes receivable	263	483
Non-Securitized | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vacation ownership notes receivable	267	493
Non-Securitized | Eligible for securitization | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vacation ownership notes receivable	54	165
Non-Securitized | Eligible for securitization | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vacation ownership notes receivable	58	175
Non-Securitized | Not eligible for securitization | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vacation ownership notes receivable	209	318
Non-Securitized | Not eligible for securitization | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Vacation ownership notes receivable	$ 209	$ 318