RETIREMENT BENEFITS - Funded Status and Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
U.S. plans | Pension plans
Change in projected benefit obligation
Projected benefit obligation at beginning of year			$ 9,741		$ 9,741
Service cost	$ 0			$ 0	0	$ 0
Interest cost on benefit obligation	124			120	374	311
Change in plan assets
Plan assets at fair value at beginning of year			10,145		10,145
Net amount recognized at period end
Benefit asset	1,144				1,144
Benefit liability	(493)				(493)
Net amount recognized on the balance sheet—Significant Plans	651				651
Amounts recognized in AOCI at period end(3)
Prior service (expense) benefit	0				0
Net actuarial (loss) gain	(6,244)				(6,244)
Net amount recognized in equity-pretax	(6,244)				(6,244)
Accumulated benefit obligation at period end—Significant Plans	9,089				9,089
U.S. plans | Pension plans | Other than Significant Plans Measured Annually
Change in projected benefit obligation
Projected benefit obligation at beginning of year			19		19
Change in plan assets
Plan assets at fair value at beginning of year			0		0
U.S. plans | Pension plans | Significant Plans Measured Quarterly
Change in projected benefit obligation
Projected benefit obligation at beginning of year		$ 9,617	9,722		9,722
Quarter activity		(265)	160
Service cost					0
Interest cost on benefit obligation					124
Actuarial (gain)					(435)
Benefits paid, net of participants’ contributions					(217)
Foreign exchange impact and other					0
Projected benefit obligation at period end—Significant Plans	9,089		9,617		9,089
Change in plan assets
Plan assets at fair value at beginning of year		10,157	10,145		10,145
Quarterly activity		(131)	143
Actual return on plan assets					(215)
Company contributions, net of reimbursements					15
Benefits paid, net of participants’ contributions					(217)
Foreign exchange impact and other					0
Plan assets at fair value at period end—Significant Plans	9,740		10,157		9,740
Funded status of the Significant Plans	651				651
U.S. plans | Postretirement benefit plans
Change in projected benefit obligation
Projected benefit obligation at beginning of year			375		375
Service cost	0			0	0	0
Interest cost on benefit obligation	4			4	13	11
Change in plan assets
Plan assets at fair value at beginning of year			253		253
Net amount recognized at period end
Benefit asset	0				0
Benefit liability	(101)				(101)
Net amount recognized on the balance sheet—Significant Plans	(101)				(101)
Amounts recognized in AOCI at period end(3)
Prior service (expense) benefit	75				75
Net actuarial (loss) gain	136				136
Net amount recognized in equity-pretax	211				211
Accumulated benefit obligation at period end—Significant Plans	323				323
U.S. plans | Postretirement benefit plans | Other than Significant Plans Measured Annually
Change in projected benefit obligation
Projected benefit obligation at beginning of year			0		0
Change in plan assets
Plan assets at fair value at beginning of year			0		0
U.S. plans | Postretirement benefit plans | Significant Plans Measured Quarterly
Change in projected benefit obligation
Projected benefit obligation at beginning of year		347	375		375
Quarter activity		(27)	(1)
Service cost					0
Interest cost on benefit obligation					4
Actuarial (gain)					(17)
Benefits paid, net of participants’ contributions					(11)
Foreign exchange impact and other					0
Projected benefit obligation at period end—Significant Plans	323		347		323
Change in plan assets
Plan assets at fair value at beginning of year		256	253		253
Quarterly activity		(2)	5
Actual return on plan assets					(3)
Company contributions, net of reimbursements					(20)
Benefits paid, net of participants’ contributions					(11)
Foreign exchange impact and other					0
Plan assets at fair value at period end—Significant Plans	222		256		222
Funded status of the Significant Plans	(101)				(101)
Non-U.S. plans | Pension plans
Change in projected benefit obligation
Projected benefit obligation at beginning of year			6,375		6,375
Service cost	29			26	87	90
Interest cost on benefit obligation	105			91	305	243
Change in plan assets
Plan assets at fair value at beginning of year			6,086		6,086
Net amount recognized at period end
Benefit asset	738				738
Benefit liability	(619)				(619)
Net amount recognized on the balance sheet—Significant Plans	119				119
Amounts recognized in AOCI at period end(3)
Prior service (expense) benefit	(3)				(3)
Net actuarial (loss) gain	(1,438)				(1,438)
Net amount recognized in equity-pretax	(1,441)				(1,441)
Accumulated benefit obligation at period end—Significant Plans	4,501				4,501
Non-U.S. plans | Pension plans | Other than Significant Plans Measured Annually
Change in projected benefit obligation
Projected benefit obligation at beginning of year			1,774		1,774
Change in plan assets
Plan assets at fair value at beginning of year			1,226		1,226
Non-U.S. plans | Pension plans | Significant Plans Measured Quarterly
Change in projected benefit obligation
Projected benefit obligation at beginning of year		5,021	4,601		4,601
Quarter activity		179	241
Service cost					12
Interest cost on benefit obligation					86
Actuarial (gain)					(264)
Benefits paid, net of participants’ contributions					(85)
Foreign exchange impact and other					(91)
Projected benefit obligation at period end—Significant Plans	4,679		5,021		4,679
Change in plan assets
Plan assets at fair value at beginning of year		5,079	4,860		4,860
Quarterly activity		(6)	225
Actual return on plan assets					(113)
Company contributions, net of reimbursements					8
Benefits paid, net of participants’ contributions					(85)
Foreign exchange impact and other					(91)
Plan assets at fair value at period end—Significant Plans	4,798		5,079		4,798
Funded status of the Significant Plans	119				119
Non-U.S. plans | Postretirement benefit plans
Change in projected benefit obligation
Projected benefit obligation at beginning of year			1,013		1,013
Service cost	0			1	1	2
Interest cost on benefit obligation	27			$ 21	79	$ 67
Change in plan assets
Plan assets at fair value at beginning of year			855		855
Net amount recognized at period end
Benefit asset	21				21
Benefit liability	0				0
Net amount recognized on the balance sheet—Significant Plans	21				21
Amounts recognized in AOCI at period end(3)
Prior service (expense) benefit	34				34
Net actuarial (loss) gain	(281)				(281)
Net amount recognized in equity-pretax	(247)				(247)
Accumulated benefit obligation at period end—Significant Plans	861				861
Non-U.S. plans | Postretirement benefit plans | Other than Significant Plans Measured Annually
Change in projected benefit obligation
Projected benefit obligation at beginning of year			193		193
Change in plan assets
Plan assets at fair value at beginning of year			7		7
Non-U.S. plans | Postretirement benefit plans | Significant Plans Measured Quarterly
Change in projected benefit obligation
Projected benefit obligation at beginning of year		965	820		820
Quarter activity		75	70
Service cost					0
Interest cost on benefit obligation					24
Actuarial (gain)					(95)
Benefits paid, net of participants’ contributions					(18)
Foreign exchange impact and other					(15)
Projected benefit obligation at period end—Significant Plans	861		965		861
Change in plan assets
Plan assets at fair value at beginning of year		945	848		848
Quarterly activity		$ 24	73
Actual return on plan assets					(29)
Company contributions, net of reimbursements					0
Benefits paid, net of participants’ contributions					(18)
Foreign exchange impact and other					(16)
Plan assets at fair value at period end—Significant Plans	882		$ 945		882
Funded status of the Significant Plans	21				21
Qualified plans | U.S. plans | Pension plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	1,144				1,144
Qualified plans | U.S. plans | Postretirement benefit plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	(101)				(101)
Qualified plans | Non-U.S. plans | Pension plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	119				119
Qualified plans | Non-U.S. plans | Postretirement benefit plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	21				21
Nonqualified plans | U.S. plans | Pension plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	(493)				(493)
Nonqualified plans | U.S. plans | Postretirement benefit plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	0				0
Nonqualified plans | Non-U.S. plans | Pension plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	0				0
Nonqualified plans | Non-U.S. plans | Postretirement benefit plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	$ 0				$ 0