BUSINESS SEGMENTS - Depreciation and Amortization (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Depreciation, amortization, and other	[1]	$ 290	$ 168	$ 139
Total segment | North American Full-Service
Segment Reporting Information [Line Items]
Depreciation, amortization, and other		111	67	55
Total segment | North American Limited-Service
Segment Reporting Information [Line Items]
Depreciation, amortization, and other		26	23	21
Total segment | Asia Pacific
Segment Reporting Information [Line Items]
Depreciation, amortization, and other		36	12	5
Total segment | Other International
Segment Reporting Information [Line Items]
Depreciation, amortization, and other		87	45	35
Unallocated corporate
Segment Reporting Information [Line Items]
Depreciation, amortization, and other		$ 30	$ 21	$ 23

[1] See Footnote 19 “Related Party Transactions” for disclosure of related party amounts.