PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Estimated Future Benefit Payments) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 24,900	$ 22,500
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	24,908	22,544	$ 23,401
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2019	1,561
2020	1,571
2021	1,603
2022	1,636
2023	1,646
2025-2029	8,523
Total	16,540
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	0	$ 0	$ 0
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2019	129
2020	124
2021	121
2022	118
2023	114
2025-2029	496
Total	$ 1,102