ENVIRONMENTAL (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Environmental Remediation Obligations [Abstract]
Gross Recoveries from Third Parties of Costs Incurred and Expensed in Prior Periods	$ 120.0		$ 120.0
Environmental Remediation Expense	(0.8)	$ 1.8	5.9	$ 6.2
Recoveries From Third Parties Of Costs Incurred And Expensed	(110.0)	0.0	(110.0)	0.0
Total Environmental Income Expense	(110.8)	$ 1.8	(104.1)	$ 6.2
Environmental Possible Additional Contingent Environmental Liabilities	$ 10.0		$ 10.0
Reserves for future environmental expenditures - total					$ 129.0	$ 131.6	$ 135.3
Reserves for future environmental expenditures - noncurrent					$ 109.0	$ 111.6	$ 118.3