RETIREMENT BENEFITS - Assumptions Used (Details)	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2018	Dec. 31, 2017
U.S. | Postretirement Benefit Plans
Plan Assumptions - During the year
Discount rate	3.90%	3.50%
Plan Assumptions - At year end
Discount rate	4.20%		3.90%	3.50%
Non-U.S. plans | Pension Plans | Weighted Average
Plan Assumptions - During the year
Discount rate	4.86%	4.75%
Plan Assumptions - At year end
Discount rate	4.88%		4.86%	4.75%
Non-U.S. plans | Pension Plans | Minimum
Plan Assumptions - During the year
Discount rate	0.75%	0.60%
Plan Assumptions - At year end
Discount rate	0.80%		0.75%	0.60%
Non-U.S. plans | Pension Plans | Maximum
Plan Assumptions - During the year
Discount rate	9.90%	10.20%
Plan Assumptions - At year end
Discount rate	10.70%		9.90%	10.20%
Non-U.S. plans | Postretirement Benefit Plans
Plan Assumptions - During the year
Discount rate	9.50%	9.55%
Plan Assumptions - At year end
Discount rate	9.50%		9.50%	9.55%
Qualified plans | U.S. | Pension Plans
Plan Assumptions - During the year
Discount rate	3.95%	3.60%
Plan Assumptions - At year end
Discount rate	4.25%		3.95%	3.60%
Nonqualified plans | U.S. | Pension Plans
Plan Assumptions - During the year
Discount rate	3.95%	3.60%
Plan Assumptions - At year end
Discount rate	4.25%		3.95%	3.60%