PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 100	$ 95	$ 298	$ 302
Interest cost	191	227	574	695
Expected return on plan assets	(415)	(420)	(1,241)	(1,258)
Amortization of prior service credit	(4)	(5)	(14)	(16)
Amortization of net (gain) loss	194	147	578	426
Curtailment/special termination benefits 1	0	0	0	(27)
Net periodic benefit cost - including discontinued operations	66	44	195	122
Net periodic benefit cost	66	44	195	101
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	250		250
Defined Benefit Plan, Plan Assets, Contributions by Employer			188
Pension Plan [Member] | Discontinued Operations [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	0	0	0	21
Other Postretirement Benefits [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	2	2	6	6
Interest cost	10	12	29	38
Amortization of net (gain) loss	(2)	(5)	(7)	(16)
Curtailment/special termination benefits 1	0	0	0	(3)
Net periodic benefit cost	$ 10	$ 9	$ 28	$ 25