RETIREMENT BENEFITS - Funded Status and Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 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	123		105	250	191
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	1,063			1,063
Benefit liability	(523)			(523)
Net amount recognized on the balance sheet—Significant Plans	540			540
Amounts recognized in AOCI at period end(3)
Prior service (expense) benefit	0			0
Net actuarial (loss) gain	(6,343)			(6,343)
Net amount recognized in equity-pretax	(6,343)			(6,343)
Accumulated benefit obligation at period end—Significant Plans	9,617			9,617
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	9,882	9,722		9,722
Quarter activity		160
Service cost				0
Interest cost on benefit obligation				122
Actuarial (gain)				(157)
Benefits paid, net of participants’ contributions				(230)
Foreign exchange impact and other				0
Projected benefit obligation at period end—Significant Plans	9,617	9,882		9,617
Change in plan assets
Plan assets at fair value at beginning of year	10,288	10,145		10,145
Quarterly activity		143
Actual return on plan assets				86
Company contributions, net of reimbursements				13
Benefits paid, net of participants’ contributions				(230)
Foreign exchange impact and other				0
Plan assets at fair value at period end—Significant Plans	10,157	10,288		10,157
Funded status of the Significant Plans	540			540
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	9	7
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	(91)			(91)
Net amount recognized on the balance sheet—Significant Plans	(91)			(91)
Amounts recognized in AOCI at period end(3)
Prior service (expense) benefit	78			78
Net actuarial (loss) gain	127			127
Net amount recognized in equity-pretax	205			205
Accumulated benefit obligation at period end—Significant Plans	347			347
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	374	375		375
Quarter activity		(1)
Service cost				0
Interest cost on benefit obligation				4
Actuarial (gain)				(20)
Benefits paid, net of participants’ contributions				(11)
Foreign exchange impact and other				0
Projected benefit obligation at period end—Significant Plans	347	374		347
Change in plan assets
Plan assets at fair value at beginning of year	258	253		253
Quarterly activity		5
Actual return on plan assets				2
Company contributions, net of reimbursements				7
Benefits paid, net of participants’ contributions				(11)
Foreign exchange impact and other				0
Plan assets at fair value at period end—Significant Plans	256	258		256
Funded status of the Significant Plans	(91)			(91)
Non-U.S. plans | Pension Plans
Change in projected benefit obligation
Projected benefit obligation at beginning of year		6,375		6,375
Service cost	30		30	58	64
Interest cost on benefit obligation	102		79	200	152
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	737			737
Benefit liability	(679)			(679)
Net amount recognized on the balance sheet—Significant Plans	58			58
Amounts recognized in AOCI at period end(3)
Prior service (expense) benefit	(2)			(2)
Net actuarial (loss) gain	(1,561)			(1,561)
Net amount recognized in equity-pretax	(1,563)			(1,563)
Accumulated benefit obligation at period end—Significant Plans	4,839			4,839
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	4,842	4,601		4,601
Quarter activity		241
Service cost				12
Interest cost on benefit obligation				84
Actuarial (gain)				3
Benefits paid, net of participants’ contributions				(83)
Foreign exchange impact and other				163
Projected benefit obligation at period end—Significant Plans	5,021	4,842		5,021
Change in plan assets
Plan assets at fair value at beginning of year	5,085	4,860		4,860
Quarterly activity		225
Actual return on plan assets				(75)
Company contributions, net of reimbursements				9
Benefits paid, net of participants’ contributions				(83)
Foreign exchange impact and other				143
Plan assets at fair value at period end—Significant Plans	5,079	5,085		5,079
Funded status of the Significant Plans	58			58
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		0	1	1
Interest cost on benefit obligation	27		$ 23	52	$ 46
Change in plan assets
Plan assets at fair value at beginning of year		855		855
Net amount recognized at period end
Benefit asset	0			0
Benefit liability	(20)			(20)
Net amount recognized on the balance sheet—Significant Plans	(20)			(20)
Amounts recognized in AOCI at period end(3)
Prior service (expense) benefit	36			36
Net actuarial (loss) gain	(335)			(335)
Net amount recognized in equity-pretax	(299)			(299)
Accumulated benefit obligation at period end—Significant Plans	965			965
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	890	820		820
Quarter activity		70
Service cost				0
Interest cost on benefit obligation				23
Actuarial (gain)				23
Benefits paid, net of participants’ contributions				(19)
Foreign exchange impact and other				48
Projected benefit obligation at period end—Significant Plans	965	890		965
Change in plan assets
Plan assets at fair value at beginning of year	921	848		848
Quarterly activity		73
Actual return on plan assets				(4)
Company contributions, net of reimbursements				0
Benefits paid, net of participants’ contributions				(19)
Foreign exchange impact and other				47
Plan assets at fair value at period end—Significant Plans	945	$ 921		945
Funded status of the Significant Plans	(20)			(20)
Qualified plans | U.S. Plans | Pension Plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	1,063			1,063
Qualified plans | U.S. Plans | Postretirement Benefit Plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	(91)			(91)
Qualified plans | Non-U.S. plans | Pension Plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	58			58
Qualified plans | Non-U.S. plans | Postretirement Benefit Plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	(20)			(20)
Nonqualified plans | U.S. Plans | Pension Plans | Significant Plans Measured Quarterly
Change in plan assets
Funded status of the Significant Plans	(523)			(523)
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