COMMITMENTS AND CONTINGENCIES - Guarantees (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	$ 377
Recorded Liability for Guarantees	130
Debt service
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	130
Recorded Liability for Guarantees	18
Operating profit
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	237
Recorded Liability for Guarantees	110
Other
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	10
Recorded Liability for Guarantees	2
Times Square Edition
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	315
Recorded Liability for Guarantees	$ 2
Loan commitment, put option agreement, obligation to acquire property, term	2 years
Loan commitment, put option agreement, obligation to acquire property, extended term	3 years
Sheraton Grand Chicago Hotel
Commitments and Contingencies Disclosure [Line Items]
Recorded Liability for Guarantees	$ 57
Sheraton Grand Chicago Hotel | Land and Hotel
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	300
Sheraton Grand Chicago Hotel | Land
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	200
Not Yet In Effect Condition | Debt service
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	6
Not Yet In Effect Condition | Operating profit
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	40
Not Yet In Effect Condition | Other
Commitments and Contingencies Disclosure [Line Items]
Maximum Potential Amount of Future Fundings	2
Accrued Expenses and Other
Commitments and Contingencies Disclosure [Line Items]
Recorded Liability for Guarantees	3
Other noncurrent liabilities
Commitments and Contingencies Disclosure [Line Items]
Recorded Liability for Guarantees	$ 127
Minimum
Commitments and Contingencies Disclosure [Line Items]
Guarantee obligations, term	3 years
Maximum
Commitments and Contingencies Disclosure [Line Items]
Guarantee obligations, term	10 years