EMPLOYEE BENEFIT PLANS - NET PENSION EXPENSE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	$ 11	$ 0	$ 0
Qualified Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	46	42	48
Interest cost	75	89	79
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	110	95	107
Amortization of prior service cost	(1)	(1)	(1)
Defined Benefit Plan, Amortization of Gain (Loss)	(35)	(37)	(33)
Net pension expense	$ 56	$ 72	$ 52