PROPERTY, PLANT AND EQUIPMENT - Operating Lease Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Property, Plant and Equipment [Abstract]
Long-term (fixed)	$ 170	$ 180	$ 529	$ 625
Long-term (variable)	47	40	92	111
Short-term	39	60	162	150
Total operating lease expense	$ 256	$ 281	$ 784	$ 887