PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS Components of Net Periodic Benefit Costs (Credits) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 10	$ 9	$ 28	$ 26
Interest cost	58	66	177	198
Expected return on plan assets	(100)	(101)	(300)	(306)
Amortization of actuarial loss	56	48	169	145
Amortization of prior service cost	1	1	3	3
Total net periodic benefit cost	25	23	77	66
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Interest cost	2	2	5	6
Amortization of actuarial loss	2	2	6	6
Amortization of prior service cost	(2)	(2)	(6)	(6)
Total net periodic benefit cost	$ 2	$ 2	$ 5	$ 6