RETIREMENT BENEFITS - Defined Contribution Plans and Postemployment Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Postemployment Retirement Benefits
Defined Benefit Plan Disclosure
Interest cost on benefit obligation	$ 0	$ 1	$ 0	$ 1
Amortization of unrecognized:
Net actuarial loss	1	0	2	1
Total service-related expense	1	1	2	2
Non-service-related expense	3	4	7	12
Total net (benefit) expense	4	5	9	14
U.S. | Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Company's contributions for defined contribution plans	113	101	324	304
Interest cost on benefit obligation	3	4	9	14
Amortization of unrecognized:
Total net (benefit) expense	(3)	0	(9)	1
Non-U.S. plans | Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Company's contributions for defined contribution plans	87	73	270	223
Interest cost on benefit obligation	25	22	74	68
Amortization of unrecognized:
Total net (benefit) expense	$ 7	$ 8	$ 20	$ 26