FINANCIAL INSTRUMENTS - Carrying Values and Estimated Fair Values - Non-securitized Notes Receivable (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	$ 1,681	$ 1,388
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	1,717	1,413
Securitized Vacation Ownership Notes Receivable | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	1,169	1,070
Securitized Vacation Ownership Notes Receivable | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	1,199	1,093
Non-Securitized Vacation Ownership Notes Receivable | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	512	318
Non-Securitized Vacation Ownership Notes Receivable | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	518	320
Non-Securitized Vacation Ownership Notes Receivable | Eligible for securitization | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	214	85
Non-Securitized Vacation Ownership Notes Receivable | Eligible for securitization | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	220	87
Non-Securitized Vacation Ownership Notes Receivable | Not eligible for securitization | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	298	233
Non-Securitized Vacation Ownership Notes Receivable | Not eligible for securitization | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	298	233
Originated | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	1,681	1,388
Originated | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Originated vacation ownership notes receivable	$ 1,717	$ 1,413