SUPPLEMENTAL GUARANTOR FINANCIAL INFORMATION (Cash Flows)(Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Supplemental Guarantor Financial Information Statements Of Cash Flows [Line Items]
Net Cash Provided by (Used in) Operating Activities	$ 455.1	$ 407.1
Payments to Acquire Property, Plant, and Equipment	(210.0)	(199.4)
Business acquired in purchase transaction, net of cash acquired	0.0	(69.5)
Payments under long-term supply contracts	(209.4)	(175.7)
Proceeds from sale/leaseback of equipment	0.0	40.4
Proceeds from disposition of property, plant and equipment	0.1	0.4
Proceeds from Contributions from Affiliates		6.6
Net investing activities	(419.3)	(397.2)
Proceeds from Issuance of Long-term Debt	2,035.0	0.0
Long-term debt repayments	(1,907.4)	(176.1)
Stock options exercised	18.5	0.4
Payments of Dividends	(99.6)	(99.1)
Debt issuance costs	(11.2)	(0.8)
Intercompany Financing Activities	0.0	0.0
Net financing activities	35.3	(275.6)
Effect of exchange rate changes on cash and cash equivalents	0.3	0.7
Net increase (decrease) in cash and cash equivalents	71.4	(265.0)
Cash and cash equivalents, end of period	255.9	127.0
Parent Guarantor
Supplemental Guarantor Financial Information Statements Of Cash Flows [Line Items]
Net Cash Provided by (Used in) Operating Activities	290.3	409.0
Payments to Acquire Property, Plant, and Equipment	(64.5)	(39.2)
Business acquired in purchase transaction, net of cash acquired		(69.5)
Payments under long-term supply contracts	0.0	0.0
Proceeds from sale/leaseback of equipment		0.0
Proceeds from disposition of property, plant and equipment	0.0	0.1
Proceeds from Contributions from Affiliates		6.6
Net investing activities	(64.5)	(102.0)
Proceeds from Issuance of Long-term Debt	620.0
Long-term debt repayments	(590.5)	(125.5)
Stock options exercised	18.5	0.4
Payments of Dividends	(99.6)	(99.1)
Debt issuance costs	(8.3)	0.0
Intercompany Financing Activities	(154.2)	(186.7)
Net financing activities	(214.1)	(410.9)
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Net increase (decrease) in cash and cash equivalents	11.7	(103.9)
Cash and cash equivalents, end of period	36.9	15.5
Issuer
Supplemental Guarantor Financial Information Statements Of Cash Flows [Line Items]
Net Cash Provided by (Used in) Operating Activities	0.0	0.0
Payments to Acquire Property, Plant, and Equipment	0.0	0.0
Business acquired in purchase transaction, net of cash acquired		0.0
Payments under long-term supply contracts	0.0	0.0
Proceeds from sale/leaseback of equipment		0.0
Proceeds from disposition of property, plant and equipment	0.0	0.0
Proceeds from Contributions from Affiliates		0.0
Net investing activities	0.0	0.0
Proceeds from Issuance of Long-term Debt	1,375.0
Long-term debt repayments	(1,316.9)	(50.6)
Stock options exercised	0.0	0.0
Payments of Dividends	0.0	0.0
Debt issuance costs	(2.9)	(0.8)
Intercompany Financing Activities	(55.2)	51.4
Net financing activities	0.0	0.0
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Net increase (decrease) in cash and cash equivalents	0.0	0.0
Cash and cash equivalents, end of period	0.0	0.0
Subsidiary Non-Guarantor
Supplemental Guarantor Financial Information Statements Of Cash Flows [Line Items]
Net Cash Provided by (Used in) Operating Activities	164.8	(1.9)
Payments to Acquire Property, Plant, and Equipment	(145.5)	(160.2)
Business acquired in purchase transaction, net of cash acquired		0.0
Payments under long-term supply contracts	(209.4)	(175.7)
Proceeds from sale/leaseback of equipment		40.4
Proceeds from disposition of property, plant and equipment	0.1	0.3
Proceeds from Contributions from Affiliates		0.0
Net investing activities	(354.8)	(295.2)
Proceeds from Issuance of Long-term Debt	40.0
Long-term debt repayments	0.0	0.0
Stock options exercised	0.0	0.0
Payments of Dividends	0.0	0.0
Debt issuance costs	0.0	0.0
Intercompany Financing Activities	209.4	135.3
Net financing activities	249.4	135.3
Effect of exchange rate changes on cash and cash equivalents	0.3	0.7
Net increase (decrease) in cash and cash equivalents	59.7	(161.1)
Cash and cash equivalents, end of period	219.0	111.5
Eliminations
Supplemental Guarantor Financial Information Statements Of Cash Flows [Line Items]
Net Cash Provided by (Used in) Operating Activities	0.0	0.0
Payments to Acquire Property, Plant, and Equipment	0.0	0.0
Business acquired in purchase transaction, net of cash acquired		0.0
Payments under long-term supply contracts	0.0	0.0
Proceeds from sale/leaseback of equipment		0.0
Proceeds from disposition of property, plant and equipment	0.0	0.0
Proceeds from Contributions from Affiliates		0.0
Net investing activities	0.0	0.0
Proceeds from Issuance of Long-term Debt	0.0
Long-term debt repayments	0.0	0.0
Stock options exercised	0.0	0.0
Payments of Dividends	0.0	0.0
Debt issuance costs	0.0	0.0
Intercompany Financing Activities	0.0	0.0
Net financing activities	0.0	0.0
Effect of exchange rate changes on cash and cash equivalents	0.0	0.0
Net increase (decrease) in cash and cash equivalents	0.0	0.0
Cash and cash equivalents, end of period	$ 0.0	$ 0.0