PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS Components of Net Periodic Benefit Costs (Credits) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 8	$ 8	$ 16	$ 18
Interest cost	40	59	83	119
Expected return on plan assets	(54)	(100)	(116)	(200)
Amortization of actuarial loss	28	52	58	113
Amortization of prior service cost (credit)	1	1	2	2
Settlement charge	(6)	0	449	0
Total net periodic benefit cost	17	20	492	52
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Interest cost	1	1	3	3
Amortization of actuarial loss	2	2	4	4
Amortization of prior service cost (credit)	(2)	(2)	(3)	(4)
Total net periodic benefit cost	$ 1	$ 1	$ 4	$ 3