EQUITY (Accumulated balances related to each component of other comprehensive income/(loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	$ (216)	$ 65	$ 86
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	7	(7)	(9)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	(209)	58	77
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	(54)	(103)	(4)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	7	13	(3)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(47)	(90)	(7)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax	(270)	(38)	82
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	14	6	(12)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax	(256)	(32)	70
Pension and postretirement benefits - Actuarial gains/(losses), Pre-tax	(134)	(143)	(89)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	25	28	(3)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax	(109)	(115)	(92)
Pension and postretirement benefits - Amortization, Pre-tax	33	55	65
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax	(6)	(11)	(13)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	27	44	52
Pension and postretirement benefits - Settlements and curtailments, Pre-tax	10	1,640	121
Other Comprehensive Income (Loss), Defined Benefit Plan, Adjustment for Settlement or Curtailment Gain (Loss), Tax	(3)	(366)	(28)
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax	7	1,274	93
Pension and other postretirement benefits, Pre-tax	(91)	1,552	97
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	16	(349)	(44)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	(75)	1,203	53
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments and Tax	7	42	(30)
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax	(1)	(9)	5
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments, after Tax	6	33	(25)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax	(1)	3	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	0	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax	(1)	3	0
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax	6	45	(30)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax	(1)	(9)	5
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax	5	36	(25)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax	(19)	43	(245)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	26	(8)	(9)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	7	35	(254)
Other Comprehensive Income/(Loss), before Tax	(374)	1,602	(96)
Other Comprehensive Income (Loss), Tax	55	(360)	(60)
Other Comprehensive Income (Loss), Net of Tax	(319)	1,242	$ (156)
Derivatives qualifying as cash flow hedges	(237)	19
Pension and other postretirement benefits	(974)	(899)
Available-for-sale securities	11	6
Foreign currency translation	(639)	(646)
Accumulated other comprehensive loss	$ (1,839)	$ (1,520)