RETIREMENT BENEFITS - Assumptions Used (Details)	3 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
U.S. | Postretirement Benefit Plans
Plan Assumptions - During the year
Discount rate	4.20%	3.90%
Plan Assumptions - At year end
Discount rate	4.20%	4.20%	3.90%
Non-U.S. plans | Pension Plans | Weighted Average
Plan Assumptions - During the year
Discount rate	4.88%	4.86%
Plan Assumptions - At year end
Discount rate	5.08%	4.88%	4.86%
Non-U.S. plans | Pension Plans | Minimum
Plan Assumptions - During the year
Discount rate	0.80%	0.75%
Plan Assumptions - At year end
Discount rate	0.95%	0.80%		0.75%
Non-U.S. plans | Pension Plans | Maximum
Plan Assumptions - During the year
Discount rate	10.70%	9.90%
Plan Assumptions - At year end
Discount rate	10.75%	10.70%		9.90%
Non-U.S. plans | Postretirement Benefit Plans
Plan Assumptions - During the year
Discount rate	9.50%	9.50%
Plan Assumptions - At year end
Discount rate	10.10%	9.50%	9.50%
Qualified plans | U.S. | Pension Plans
Plan Assumptions - During the year
Discount rate	4.25%	3.95%
Plan Assumptions - At year end
Discount rate	4.30%	4.25%	3.95%
Nonqualified plans | U.S. | Pension Plans
Plan Assumptions - During the year
Discount rate	4.25%	3.95%
Plan Assumptions - At year end
Discount rate	4.30%	4.25%	3.95%