RETIREMENT BENEFITS - Assumptions Used (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
U.S. | Postretirement Benefit Plans
Plan Assumptions - During the year
Discount rate	3.15%	3.00%
Plan Assumptions - At year end
Discount rate	3.20%	3.15%	3.80%
Non-U.S. plans | Pension Plans | Weighted Average
Plan Assumptions - During the year
Discount rate	4.21%	4.05%
Plan Assumptions - At year end
Discount rate	4.38%	4.21%	4.74%
Non-U.S. plans | Pension Plans | Minimum
Plan Assumptions - During the year
Discount rate	0.20%	(0.05%)
Plan Assumptions - At year end
Discount rate	0.45%	0.20%	0.45%
Non-U.S. plans | Pension Plans | Maximum
Plan Assumptions - During the year
Discount rate	8.95%	9.00%
Plan Assumptions - At year end
Discount rate	9.45%	8.95%	10.30%
Non-U.S. plans | Postretirement Benefit Plans
Plan Assumptions - During the year
Discount rate	9.10%	9.20%
Plan Assumptions - At year end
Discount rate	9.75%	9.10%	10.30%
Qualified plans | U.S. | Pension Plans
Plan Assumptions - During the year
Discount rate	3.25%	3.10%
Plan Assumptions - At year end
Discount rate	3.20%	3.25%	3.85%
Nonqualified plans | U.S. | Pension Plans
Plan Assumptions - During the year
Discount rate	3.25%	3.10%
Plan Assumptions - At year end
Discount rate	3.25%	3.25%	3.90%