RETIREMENT BENEFITS - Defined Contribution Plans and Postemployment Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Postemployment Retirement Benefits
Defined Benefit Plan Disclosure
Interest cost on benefit obligation	$ 0	$ 1	$ 0	$ 1
Expected return on plan assets	0	(1)	0	(1)
Amortization of unrecognized:
Net actuarial loss	1	0	1	1
Total service-related benefit	1	0	1	1
Non-service-related expense	3	2	8	6
Total net (benefit) expense	4	2	9	7
U.S. | Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Company's contributions for defined contribution plans	101	99	203	198
Interest cost on benefit obligation	5	6	10	13
Expected return on plan assets	(4)	(4)	(9)	(9)
Amortization of unrecognized:
Total net (benefit) expense	1	2	1	4
Non-U.S. plans | Postretirement Benefit Plans
Defined Benefit Plan Disclosure
Company's contributions for defined contribution plans	74	71	150	139
Interest cost on benefit obligation	22	26	46	52
Expected return on plan assets	(18)	(21)	(38)	(42)
Amortization of unrecognized:
Total net (benefit) expense	$ 9	$ 10	$ 18	$ 20