RETIREMENT BENEFITS PLANS - Change in Benefit Obligations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension plans | United States
Change in benefit obligations
Balance at January 1	$ 4,121	$ 4,028
Service cost	37	97	$ 91
Interest cost	70	103	138
Actuarial (gain) loss	(82)	223
Gross benefits paid	(435)	(330)
Currency translation	0	0
Plan amendments	1	0
Acquisitions and divestitures	48	0
Benefit obligation reclassified to held for sale	0	0
Other	0	0
Balance at December 31	3,760	4,121	4,028
Accumulated benefit obligation	3,707	4,054
Pension plans | Foreign Plan
Change in benefit obligations
Balance at January 1	3,036	2,747
Service cost	72	73	58
Interest cost	40	45	57
Actuarial (gain) loss	(143)	217
Gross benefits paid	(107)	(121)
Currency translation	(79)	137
Plan amendments	0	1
Acquisitions and divestitures	14	0
Benefit obligation reclassified to held for sale	0	(65)
Other	4	2
Balance at December 31	2,837	3,036	2,747
Accumulated benefit obligation	2,709	2,862
Other postretirement benefits plans
Change in benefit obligations
Balance at January 1	375	378
Service cost	1	2	2
Interest cost	6	9	14
Actuarial (gain) loss	(59)	11
Gross benefits paid	(36)	(49)
Currency translation	0	2
Plan amendments	0	0
Acquisitions and divestitures	2	0
Benefit obligation reclassified to held for sale	0	0
Other	15	22
Balance at December 31	$ 304	$ 375	$ 378