RETIREMENT BENEFITS PLANS - Change in Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in plan assets
Balance at January 1	$ 5,600
Balance at December 31	5,919	$ 5,600
Pension plans
Change in plan assets
Employer contributions	343	122	$ 119
Pension plans | United States
Change in plan assets
Balance at January 1	3,463	3,433
Actual return on plan assets	380	342
Employer contributions	237	18	17
Gross benefits paid	(435)	(330)
Currency translation	0	0
Acquisitions and divestitures	27	0
Plan assets reclassified to held for sale	0	0
Other	0	0
Balance at December 31	3,672	3,463	3,433
Pension plans | Foreign Plan
Change in plan assets
Balance at January 1	2,137	1,903
Actual return on plan assets	127	185
Employer contributions	106	104	102
Gross benefits paid	(107)	(121)
Currency translation	(23)	69
Acquisitions and divestitures	4	0
Plan assets reclassified to held for sale	0	(5)
Other	3	2
Balance at December 31	2,247	2,137	1,903
Other postretirement benefits plans
Change in plan assets
Balance at January 1	20	23
Actual return on plan assets	0	1
Employer contributions	20	23
Gross benefits paid	(36)	(49)
Currency translation	0	0
Acquisitions and divestitures	0	0
Plan assets reclassified to held for sale	0	0
Other	15	22
Balance at December 31	$ 19	$ 20	$ 23