RETIREMENT BENEFITS - Net (Benefit) Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
U.S. | Pension Plans
Service-related expense
Benefits earned during the period	$ 0	$ 0
Interest cost on benefit obligation	86	82
Expected return on plan assets	(154)	(182)
Amortization of unrecognized:
Prior service cost (benefit)	1	1
Net actuarial loss (gain)	56	62
Total net expense	(11)	(37)
U.S. | Postretirement Benefit Plans
Service-related expense
Benefits earned during the period	0	0
Interest cost on benefit obligation	3	3
Expected return on plan assets	(3)	(4)
Amortization of unrecognized:
Prior service cost (benefit)	(2)	(2)
Net actuarial loss (gain)	(1)	0
Total net expense	(3)	(3)
Non-U.S. plans | Pension Plans
Service-related expense
Benefits earned during the period	34	39
Interest cost on benefit obligation	73	62
Expected return on plan assets	(66)	(61)
Amortization of unrecognized:
Prior service cost (benefit)	(2)	(1)
Net actuarial loss (gain)	13	18
Total net expense	52	57
Non-U.S. plans | Postretirement Benefit Plans
Service-related expense
Benefits earned during the period	1	2
Interest cost on benefit obligation	23	25
Expected return on plan assets	(20)	(22)
Amortization of unrecognized:
Prior service cost (benefit)	(3)	(2)
Net actuarial loss (gain)	1	5
Total net expense	$ 2	$ 8