EMPLOYEE BENEFIT PLANS - Components of Certain Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Retirement Benefits [Abstract]
Service cost	$ 3	$ 2	$ 7	$ 8
Interest cost	23	30	68	91
Expected return on assets	(36)	(37)	(110)	(114)
Actuarial (gain) loss	0	0	1	1
Net amortization	27	26	82	74
Impact of settlement	4	0	4	0
Net periodic pension expense	$ 21	$ 21	$ 52	$ 60