EQUITY (Accumulated balances related to each component of other comprehensive income/(loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	$ 86	$ (101)	$ (5)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	(9)	33	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax	77	(68)	(5)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	(4)	19	12
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	(3)	(8)	(3)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(7)	11	9
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax	82	(82)	7
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	(12)	25	(3)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax	70	(57)	4
Pension and postretirement benefits - Actuarial gains/(losses), Pre-tax	(89)	47	(126)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	(3)	11	(3)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax	(92)	58	(129)
Pension and postretirement benefits - Amortization, Pre-tax	65	77	78
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax	(13)	(31)	(25)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax	52	46	53
Pension and postretirement benefits - Settlements and curtailments, Pre-tax	121	167	91
Other Comprehensive Income (Loss), Defined Benefit Plan, Adjustment for Settlement or Curtailment Gain (Loss), Tax	(28)	(57)	(32)
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), after Tax	93	110	59
Pension and other postretirement benefits, Pre-tax	97	291	43
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	(44)	(77)	(60)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	53	214	(17)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments and Tax	(30)	38	(12)
Other Comprehensive Income (Loss), Available-for-sale Securities, before Reclassification Adjustments, Tax	5	6	(1)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments, after Tax	(25)	44	(13)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax	0	(7)	29
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax	0	2	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax	0	(5)	29
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax	(30)	31	17
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax	5	8	(1)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax	(25)	39	16
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax	(245)	(20)	(33)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	(9)	38	(5)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(254)	18	(38)
Other Comprehensive Income/(Loss), before Tax	(96)	220	34
Other Comprehensive Income (Loss), Tax	(60)	(6)	(69)
Other Comprehensive Income (Loss), Net of Tax	(156)	214	$ (35)
Derivatives qualifying as cash flow hedges	51	(19)
Pension and other postretirement benefits	(2,102)	(1,883)
Available-for-sale securities	(30)	32
Foreign currency translation	(681)	(419)
Accumulated other comprehensive loss	$ (2,762)	$ (2,289)