PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Pension Plan [Member]
Defined Benefit Plan Disclosures [Line Items]
Defined Benefit Pension Plans, Number of Plans, Including Discontinued Operations	45		45
Defined Benefit Pension Plans, Number of Plans	35		35
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 95	$ 131	$ 302	$ 396
Interest cost	227	216	695	651
Expected return on plan assets	(420)	(401)	(1,258)	(1,211)
Amortization of prior service credit	(5)	(6)	(16)	(18)
Amortization of net (gain) loss	147	168	426	509
Curtailment/special termination benefits 1	0	0	(27)	0
Net periodic benefit cost - including discontinued operations	44	108	122	327
Net periodic benefit cost	44	83	101	252
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	285		285
Defined Benefit Plan, Plan Assets, Contributions by Employer			206
Pension Plan [Member] | Discontinued Operations [Member]
Defined Benefit Plan Disclosures [Line Items]
Liability, Defined Benefit Plan, Current	270		270
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	0	25	21	75
Other Postretirement Benefits [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	2	3	6	9
Interest cost	12	11	38	33
Amortization of net (gain) loss	(5)	(6)	(16)	(18)
Curtailment/special termination benefits 1	0	0	(3)	0
Net periodic benefit cost - including discontinued operations	9	8	25	24
Net periodic benefit cost	9	8	25	22
Other Postretirement Benefits [Member] | Discontinued Operations [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	$ 0	$ 0	$ 0	$ 2