RETIREMENT BENEFITS - Defined Contribution Plans and Postemployment Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Postemployment Retirement Benefits
Amortization of unrecognized:
Net actuarial loss	$ 1	$ 1	$ 1	$ 1
Total service-related expense	1	1	1	1
Non-service-related (benefit) expense	(1)	3	4	8
Total net expense	0	4	5	9
U.S. | Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Company's contributions for defined contribution plans	106	101	211	203
Amortization of unrecognized:
Total net expense	(3)	1	(6)	1
Non-U.S. plans | Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Company's contributions for defined contribution plans	91	74	183	150
Amortization of unrecognized:
Total net expense	$ 5	$ 9	$ 13	$ 18