RESTRUCTURING - Roll Forward of Restructuring Liability (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			$ 173	$ 34
Restructuring expense, net	$ 62	$ 37	92	52
Cash payments			(121)	(30)
Foreign currency translation adjustment			0
Restructuring reserve, ending balance	144	56	144	56
Less: Non-current restructuring liability	40	13	40	13
Current restructuring liability	104	43	104	43
Employee termination benefits
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			160	34
Restructuring expense, net			57	40
Cash payments			(82)	(28)
Foreign currency translation adjustment			(1)
Restructuring reserve, ending balance	134	46	134	46
Less: Non-current restructuring liability	37	13	37	13
Current restructuring liability	97	33	97	33
Other
Restructuring Reserve [Roll Forward]
Restructuring reserve, beginning balance			13	0
Restructuring expense, net			35	12
Cash payments			(39)	(2)
Foreign currency translation adjustment			1
Restructuring reserve, ending balance	10	10	10	10
Less: Non-current restructuring liability	3	0	3	0
Current restructuring liability	$ 7	$ 10	$ 7	$ 10