INTANGIBLE ASSETS AND GOODWILL - Carrying Amount of Goodwill (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 9,039
Foreign currency translation	9
Ending balance	9,048
North American Full-Service
Goodwill [Roll Forward]
Beginning balance	3,566
Foreign currency translation	10
Ending balance	3,576
North American Limited-Service
Goodwill [Roll Forward]
Beginning balance	1,755
Foreign currency translation	7
Ending balance	1,762
Asia Pacific
Goodwill [Roll Forward]
Beginning balance	1,862
Foreign currency translation	2
Ending balance	1,864
Other International
Goodwill [Roll Forward]
Beginning balance	1,856
Foreign currency translation	(10)
Ending balance	$ 1,846