PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 10	$ 10	$ 30	$ 28
Interest cost	32	33	96	97
Expected return on plan assets	(55)	(56)	(164)	(166)
Amortization of net (gain) loss	24	20	71	62
Net periodic benefit cost	11	7	33	21
Other Postretirement Benefits [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost	2	2	5	6
Amortization of net (gain) loss	(3)	(2)	(7)	(4)
Net periodic benefit cost	$ (1)	$ 0	$ (2)	$ 2