GOODWILL AND INTANGIBLE ASSETS - Changes in Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill
Balance of goodwill at beginning of period	$ 22,256	$ 21,659	$ 22,349
Foreign exchange translation and other	(194)	729	(613)
Divestitures	(16)	(104)	(77)
Impairment of goodwill		(28)
Balance of goodwill at end of period	$ 22,046	$ 22,256	$ 21,659