BENEFIT PLANS (Net Amounts Recognized, or Funded Status of Pension and Other Postretirement Benefit Plans) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Amounts recognized in the statements of financial position consist of:
Long-term liabilities	$ (175.8)	$ (184.4)
Pension Benefits
Amounts recognized in the statements of financial position consist of:
Noncurrent assets	0.0	0.0
Current liabilities	(5.4)	(4.2)
Long-term liabilities	(165.1)	(174.1)
Funded status of plan	(170.5)	(178.3)
Other Benefits
Amounts recognized in the statements of financial position consist of:
Noncurrent assets	0.0	0.0
Current liabilities	(0.2)	(0.2)
Long-term liabilities	(6.9)	(5.7)
Funded status of plan	$ (7.1)	$ (5.9)