RETIREMENT BENEFITS - Funded Status and Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Amounts recognized in AOCI
Sum of all settlements to triger settlement accounting (percentage)	10.00%
U.S.
Change in plan assets
Plan assets at fair value at beginning of year	$ 10,398
Plan assets at fair value at year end	10,441	$ 10,398
Amounts recognized in AOCI
Net amount recognized in AOCI	13	16
U.S. | Pension Plans
Change in projected benefit obligation
Projected benefit obligation at beginning of year	9,741	12,766
Service cost	0	0	$ 0
Interest cost on benefit obligation	505	442	351
Plan amendments	0	0
Actuarial (gain)	282	(2,522)
Benefits paid, net of participants’ contributions	(888)	(945)
Divestitures	0	0
Settlement	0	0
Curtailment	0	0
Foreign exchange impact and other	0	0
Projected benefit obligation at period end	9,640	9,741	12,766
Change in plan assets
Plan assets at fair value at beginning of year	10,145	12,977
Actual return on assets	895	(1,942)
Company contributions, net of reimbursements	58	55
Benefits paid, net of participants’ contributions	(888)	(945)
Divestitures	0	0
Settlement	0	0
Foreign exchange impact and other	0	0
Plan assets at fair value at year end	10,210	10,145	12,977
Funded status of the plans at year end	570	404
Net amount recognized at year end
Net amount recognized on the balance sheet	570	404
Amounts recognized in AOCI
Prior service (cost) benefit	(5)	(6)
Net actuarial (loss) gain	(6,320)	(6,445)
Net amount recognized in AOCI	(6,325)	(6,451)
Accumulated benefit obligation at period end	9,640	9,740
U.S. | Postretirement Benefit Plans
Change in projected benefit obligation
Projected benefit obligation at beginning of year	375	501
Service cost	0	0	0
Interest cost on benefit obligation	18	16	13
Plan amendments	0	0
Actuarial (gain)	(1)	(95)
Benefits paid, net of participants’ contributions	(49)	(47)
Divestitures	0	0
Settlement	0	0
Curtailment	0	0
Foreign exchange impact and other	0	0
Projected benefit obligation at period end	343	375	501
Change in plan assets
Plan assets at fair value at beginning of year	253	319
Actual return on assets	19	(33)
Company contributions, net of reimbursements	8	14
Benefits paid, net of participants’ contributions	(49)	(47)
Divestitures	0	0
Settlement	0	0
Foreign exchange impact and other	0	0
Plan assets at fair value at year end	231	253	319
Funded status of the plans at year end	(112)	(122)
Net amount recognized at year end
Net amount recognized on the balance sheet	(112)	(122)
Amounts recognized in AOCI
Prior service (cost) benefit	73	82
Net actuarial (loss) gain	114	120
Net amount recognized in AOCI	187	202
Accumulated benefit obligation at period end	343	375
Non-U.S.
Change in plan assets
Plan assets at fair value at beginning of year	6,941
Plan assets at fair value at year end	7,396	6,941
Non-U.S. | Pension Plans
Change in projected benefit obligation
Projected benefit obligation at beginning of year	6,375	8,001
Service cost	115	116	149
Interest cost on benefit obligation	409	329	268
Plan amendments	(2)	0
Actuarial (gain)	273	(1,168)
Benefits paid, net of participants’ contributions	(368)	(397)
Divestitures	(77)	(22)
Settlement	(104)	(364)
Curtailment	(33)	(35)
Foreign exchange impact and other	442	(85)
Projected benefit obligation at period end	7,030	6,375	8,001
Change in plan assets
Plan assets at fair value at beginning of year	6,086	7,614
Actual return on assets	352	(1,212)
Company contributions, net of reimbursements	118	495
Benefits paid, net of participants’ contributions	(368)	(397)
Divestitures	(19)	(11)
Settlement	(104)	(364)
Foreign exchange impact and other	361	(39)
Plan assets at fair value at year end	6,426	6,086	7,614
Funded status of the plans at year end	(604)	(289)
Net amount recognized at year end
Net amount recognized on the balance sheet	(604)	(289)
Amounts recognized in AOCI
Prior service (cost) benefit	5	7
Net actuarial (loss) gain	(1,990)	(1,671)
Net amount recognized in AOCI	(1,985)	(1,664)
Accumulated benefit obligation at period end	6,686	6,051
Non-U.S. | Postretirement Benefit Plans
Change in projected benefit obligation
Projected benefit obligation at beginning of year	1,013	1,169
Service cost	1	2	6
Interest cost on benefit obligation	106	90	96
Plan amendments	0	0
Actuarial (gain)	27	(100)
Benefits paid, net of participants’ contributions	(77)	(72)
Divestitures	0	0
Settlement	0	0
Curtailment	0	0
Foreign exchange impact and other	138	(76)
Projected benefit obligation at period end	1,208	1,013	1,169
Change in plan assets
Plan assets at fair value at beginning of year	855	1,043
Actual return on assets	56	(75)
Company contributions, net of reimbursements	9	9
Benefits paid, net of participants’ contributions	(77)	(72)
Divestitures	0	0
Settlement	0	0
Foreign exchange impact and other	127	(50)
Plan assets at fair value at year end	970	855	$ 1,043
Funded status of the plans at year end	(238)	(158)
Net amount recognized at year end
Net amount recognized on the balance sheet	(238)	(158)
Amounts recognized in AOCI
Prior service (cost) benefit	33	36
Net actuarial (loss) gain	(311)	(206)
Net amount recognized in AOCI	(278)	(170)
Accumulated benefit obligation at period end	1,208	1,013
Qualified | U.S. | Pension Plans
Change in plan assets
Funded status of the plans at year end	1,107	949
Net amount recognized at year end
Benefit asset	1,107	949
Benefit liability	0	0
Net amount recognized on the balance sheet	1,107	949
Qualified | U.S. | Postretirement Benefit Plans
Change in plan assets
Funded status of the plans at year end	(112)	(122)
Net amount recognized at year end
Benefit asset	0	0
Benefit liability	(112)	(122)
Net amount recognized on the balance sheet	(112)	(122)
Qualified | Non-U.S. | Pension Plans
Change in plan assets
Funded status of the plans at year end	(604)	(289)
Net amount recognized at year end
Benefit asset	832	799
Benefit liability	(1,436)	(1,088)
Net amount recognized on the balance sheet	(604)	(289)
Qualified | Non-U.S. | Postretirement Benefit Plans
Change in plan assets
Funded status of the plans at year end	(238)	(158)
Net amount recognized at year end
Benefit asset	0	28
Benefit liability	(238)	(186)
Net amount recognized on the balance sheet	(238)	(158)
Nonqualified | U.S. | Pension Plans
Change in plan assets
Funded status of the plans at year end	(537)	(545)
Net amount recognized at year end
Net amount recognized on the balance sheet	(537)	(545)
Nonqualified | U.S. | Postretirement Benefit Plans
Change in plan assets
Funded status of the plans at year end	0	0
Net amount recognized at year end
Net amount recognized on the balance sheet	0	0
Nonqualified | Non-U.S. | Pension Plans
Change in plan assets
Funded status of the plans at year end	0	0
Net amount recognized at year end
Net amount recognized on the balance sheet	0	0
Nonqualified | Non-U.S. | Postretirement Benefit Plans
Change in plan assets
Funded status of the plans at year end	0	0
Net amount recognized at year end
Net amount recognized on the balance sheet	$ 0	$ 0