PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS Components of Net Periodic Benefit Costs (Credits) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 8	$ 10
Interest cost	43	60
Expected return on plan assets	(62)	(100)
Amortization of actuarial loss	30	61
Amortization of prior service cost (credit)	1	1
Accelerated Pension Benefits	455	0
Total net periodic benefit cost	475	32
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Interest cost	2	2
Amortization of actuarial loss	2	2
Amortization of prior service cost (credit)	(1)	(2)
Total net periodic benefit cost	$ 3	$ 2