PENSION AND OTHER POSTRETIREMENT BENEFITS (Estimated Future Benefit Payments) (Details) $ in Millions	Dec. 31, 2018 USD ($)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	$ 277
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	276
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	275
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	274
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	271
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	1,293
Total estimated future benefit payments	2,666
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	19
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	19
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	20
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	20
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	19
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	76
Total estimated future benefit payments	$ 173