PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)
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	$ 132	$ 207	$ 265
Interest cost	227	217	468	435
Expected return on plan assets	(421)	(404)	(838)	(810)
Amortization of prior service credit	(5)	(6)	(11)	(12)
Amortization of net (gain) loss	147	170	279	341
Curtailment/special termination benefits 1	(27)	0	(27)	0
Net periodic benefit cost - including discontinued operations	16	109	78	219
Net periodic benefit cost	16	84	57	169
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	285		285
Defined Benefit Plan, Plan Assets, Contributions by Employer			152
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	50
Other Postretirement Benefits [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	2	3	4	6
Interest cost	12	11	26	22
Amortization of net (gain) loss	(5)	(6)	(11)	(12)
Curtailment/special termination benefits 1	(3)	0	(3)	0
Net periodic benefit cost - including discontinued operations	6	8	16	16
Net periodic benefit cost	6	7	16	14
Other Postretirement Benefits [Member] | Discontinued Operations [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net periodic benefit cost	$ 0	$ 1	$ 0	$ 2