PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Net Periodic Benefit Cost) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ (20)	$ (17)	$ (1)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	35	34	39
Defined Benefit Plan, Interest Cost	112	145	128
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(200)	(210)	(218)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(1)	(1)	(1)
Defined Benefit Plan, Amortization of Gain (Loss)	110	84	95
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	56	52	43
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	1	1	1
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	(110)	(84)	(95)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax	240	202	31
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	131	119	(63)
Total recognized in net periodic benefit cost and other comprehensive loss or income	187	171	(20)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	1	1	1
Defined Benefit Plan, Interest Cost	5	7	6
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	0	0	0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0	0
Defined Benefit Plan, Amortization of Gain (Loss)	(6)	(8)	(9)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	0	0	(2)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax	0	0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	6	8	9
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax	2	11	(2)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	8	19	7
Total recognized in net periodic benefit cost and other comprehensive loss or income	$ 8	$ 19	$ 5