BUSINESS SEGMENTS - Depreciation and Amortization (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Depreciation, amortization, and other	[1]	$ 341	$ 226	$ 229
Total segment | North American Full-Service
Segment Reporting Information [Line Items]
Depreciation, amortization, and other		199	82	82
Total segment | North American Limited-Service
Segment Reporting Information [Line Items]
Depreciation, amortization, and other		19	15	14
Total segment | Asia Pacific
Segment Reporting Information [Line Items]
Depreciation, amortization, and other		25	26	32
Total segment | Other International
Segment Reporting Information [Line Items]
Depreciation, amortization, and other		71	70	71
Unallocated corporate
Segment Reporting Information [Line Items]
Depreciation, amortization, and other		$ 27	$ 33	$ 30

[1] See Note 16 for disclosure of related party amounts.