EQUITY (Accumulated balances related to each component of other comprehensive income/(loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	$ 65	$ 86	$ (101)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	(7)	(9)	33
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	58	77	(68)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	(103)	(4)	19
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	13	(3)	(8)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(90)	(7)	11
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax	(38)	82	(82)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	6	(12)	25
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax	(32)	70	(57)
Pension and postretirement benefits - Actuarial gains/(losses), Pre-tax	(143)	(89)	47
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	28	(3)	11
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax	(115)	(92)	58
Pension and postretirement benefits - Amortization, Pre-tax	55	65	77
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax	(11)	(13)	(31)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	44	52	46
Pension and postretirement benefits - Settlements and curtailments, Pre-tax	1,640	121	167
Other Comprehensive Income (Loss), Defined Benefit Plan, Adjustment for Settlement or Curtailment Gain (Loss), Tax	(366)	(28)	(57)
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax	1,274	93	110
Pension and other postretirement benefits, Pre-tax	1,552	97	291
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	(349)	(44)	(77)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	1,203	53	214
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments and Tax	42	(30)	38
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax	(9)	5	6
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments, after Tax	33	(25)	44
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax	3	0	(7)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	0	0	2
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax	3	0	(5)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax	45	(30)	31
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax	(9)	5	8
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax	36	(25)	39
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax	43	(245)	(20)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	(8)	(9)	38
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	35	(254)	18
Other Comprehensive Income/(Loss), before Tax	1,602	(96)	220
Other Comprehensive Income (Loss), Tax	(360)	(60)	(6)
Other Comprehensive Income (Loss), Net of Tax	1,242	(156)	$ 214
Derivatives qualifying as cash flow hedges	19	51
Pension and other postretirement benefits	(899)	(2,102)
Available-for-sale securities	6	(30)
Foreign currency translation	(646)	(681)
Accumulated other comprehensive loss	$ (1,520)	$ (2,762)