PENSION AND POSTRETIREMENT BENEFIT PLANS (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Net periodic benefit cost/(credit)	$ (2)		$ 26	$ (6)	$ 70
Pension and postretirement	857			857		$ 725
Defined contribution plan expense	65		50	150	90
Pension Assets Transfer		$ 381
Reversion excise tax	0	$ 76	0	76	0
Pension Benefits [Member]
Pension, Postretirement And Postemployment Liabilities Statement [Line Items]
Service cost - benefits earned during the period	12		5	24	12
Interest cost on projected benefit obligation	11		37	19	81
Expected return on plan assets	(24)		(70)	(47)	(134)
Amortization of prior service credits	(1)		(1)	(2)	(2)
Amortization of net actuarial (gain)/loss	10		17	21	35
Curtailment and settlements	2		44	4	93
Net periodic benefit cost/(credit)	10		$ 32	19	$ 85
Pension and postretirement	$ 579			$ 579		$ 569