SUPPLEMENTAL GUARANTOR FINANCIAL INFORMATION (Balance Sheet)(Details) - USD ($)
$ in Millions
Sep. 30, 2016
Dec. 31, 2015
Sep. 30, 2015
Dec. 31, 2014
Supplemental Guarantor Financial Information Balance Sheets [Line Items]        
Cash and cash equivalents $ 127.0 $ 392.0 $ 254.0 $ 256.8
Receivables, net 744.1 783.4 300.4  
Intercompany receivables 0.0 0.0 0.0  
Income taxes receivable 49.0 32.9 0.0  
Inventories 617.0 685.2 232.5  
Current deferred income taxes 0.0 0.0 69.1  
Other Assets, Current 16.1 39.9 12.4  
Total current assets 1,553.2 1,933.4 868.4  
Property, Plant and Equipment, Net 3,713.9 3,953.4 913.7  
Investment in subsidiaries 0.0 0.0 0.0  
Deferred income taxes 112.2 95.9 11.9  
Other Assets, Noncurrent 640.3 454.6 47.3  
Long-term receivables—affiliates 0.0 0.0    
Intangible Assets, Net 653.8 677.5 112.5  
Goodwill 2,119.4 2,174.1 747.1 747.1
Total assets 8,792.8 9,288.9 2,700.9  
Current installments of long-term debt 80.3 205.0 141.1  
Accounts payable 509.7 608.2 158.7  
Intercompany payables 0.0 0.0 0.0  
Income taxes payable 13.3 4.9 10.4  
Accrued Liabilities, Current 291.5 328.1 272.8  
Total current liabilities 894.8 1,146.2 583.0  
Long-term Debt, Excluding Current Maturities 3,597.5 3,643.8 521.2  
Accrued pension liability 597.7 648.9 97.2  
Deferred income taxes 1,036.6 1,095.2 118.0  
Long-term payables—affiliates 0.0 0.0    
Other Liabilities, Noncurrent 335.5 336.0 335.4  
Total liabilities 6,462.1 6,870.1 1,654.8  
Commitments and contingencies  
Common Stock, Value, Issued 165.3 165.1 77.6  
Additional Paid in Capital, Common Stock 2,242.8 2,236.4 796.2  
Accumulated other comprehensive loss (466.7) (492.5) (433.2) (443.1)
Retained Earnings (Accumulated Deficit) 389.3 509.8 605.5  
Total shareholders' equity 2,330.7 2,418.8 1,046.1 1,013.3
Liabilities and Equity 8,792.8 9,288.9 2,700.9  
Parent Guarantor        
Supplemental Guarantor Financial Information Balance Sheets [Line Items]        
Cash and cash equivalents 15.5 119.4 224.2 239.4
Receivables, net 64.4 107.7 110.2  
Intercompany receivables 0.0 0.0 0.0  
Income taxes receivable 38.5 27.3    
Inventories 163.8 166.0 159.2  
Current deferred income taxes   0.0 57.8  
Other Assets, Current 145.5 152.1 115.8  
Total current assets 427.7 572.5 667.2  
Property, Plant and Equipment, Net 451.4 508.7 508.0  
Investment in subsidiaries 6,000.5 5,905.0 1,811.9  
Deferred income taxes 153.7 155.6 61.4  
Other Assets, Noncurrent 40.4 43.5 36.8  
Long-term receivables—affiliates 0.0 0.0    
Intangible Assets, Net 0.4 0.5 0.5  
Goodwill 0.0 0.0 0.0  
Total assets 7,074.1 7,185.8 3,085.8  
Current installments of long-term debt 68.1 192.8 128.9  
Accounts payable 55.4 37.3 60.3  
Intercompany payables 1,740.8 1,169.2 770.7  
Income taxes payable 0.0 1.5 10.4  
Accrued Liabilities, Current 158.1 227.8 202.2  
Total current liabilities 2,022.4 1,628.6 1,172.5  
Long-term Debt, Excluding Current Maturities 1,087.4 1,084.0 496.5  
Accrued pension liability 141.3 484.3 96.1  
Deferred income taxes 0.0 0.0 0.0  
Long-term payables—affiliates 1,226.0 1,296.4    
Other Liabilities, Noncurrent 266.3 273.7 274.6  
Total liabilities 4,743.4 4,767.0 2,039.7  
Common Stock, Value, Issued 165.3 165.1 77.6  
Additional Paid in Capital, Common Stock 2,242.8 2,236.4 796.2  
Accumulated other comprehensive loss (466.7) (492.5) (433.2)  
Retained Earnings (Accumulated Deficit) 389.3 509.8 605.5  
Total shareholders' equity 2,330.7 2,418.8 1,046.1  
Liabilities and Equity 7,074.1 7,185.8 3,085.8  
Issuer        
Supplemental Guarantor Financial Information Balance Sheets [Line Items]        
Cash and cash equivalents 0.0 0.0 0.0 0.0
Receivables, net 0.0 0.0 0.0  
Intercompany receivables 8.3 76.1 0.0  
Income taxes receivable 0.0 0.0    
Inventories 0.0 0.0 0.0  
Current deferred income taxes   0.0 0.0  
Other Assets, Current 0.0 5.0 0.0  
Total current assets 8.3 81.1 0.0  
Property, Plant and Equipment, Net 0.0 0.0 0.0  
Investment in subsidiaries 3,690.5 3,636.3 0.0  
Deferred income taxes 0.0 0.0 0.0  
Other Assets, Noncurrent 0.0 0.0 0.0  
Long-term receivables—affiliates 2,492.8 2,562.6    
Intangible Assets, Net 5.7 0.0 0.0  
Goodwill 966.3 990.2 0.0  
Total assets 7,163.6 7,270.2 0.0  
Current installments of long-term debt 0.0 0.0 0.0  
Accounts payable 0.0 0.0 0.0  
Intercompany payables 0.0 0.0 0.0  
Income taxes payable 0.0 0.0 0.0  
Accrued Liabilities, Current 0.0 0.0 0.0  
Total current liabilities 0.0 0.0 0.0  
Long-term Debt, Excluding Current Maturities 2,497.8 2,547.4 0.0  
Accrued pension liability 0.0 0.0 0.0  
Deferred income taxes 241.5 294.8 0.0  
Long-term payables—affiliates 281.7 286.5    
Other Liabilities, Noncurrent 0.0 0.0 0.0  
Total liabilities 3,021.0 3,128.7 0.0  
Common Stock, Value, Issued 0.0 0.0 0.0  
Additional Paid in Capital, Common Stock 4,125.7 4,146.1 0.0  
Accumulated other comprehensive loss 0.0 0.0 0.0  
Retained Earnings (Accumulated Deficit) 16.9 (4.6) 0.0  
Total shareholders' equity 4,142.6 4,141.5 0.0  
Liabilities and Equity 7,163.6 7,270.2 0.0  
Subsidiary Non-Guarantor        
Supplemental Guarantor Financial Information Balance Sheets [Line Items]        
Cash and cash equivalents 111.5 272.6 29.8 17.4
Receivables, net 679.7 679.4 190.2  
Intercompany receivables 1,732.5 1,093.1 770.7  
Income taxes receivable 11.1 5.7    
Inventories 453.2 519.2 73.3  
Current deferred income taxes   2.7 11.3  
Other Assets, Current 4.2 4.6 2.1  
Total current assets 2,992.2 2,577.3 1,077.4  
Property, Plant and Equipment, Net 3,262.5 3,444.7 405.7  
Investment in subsidiaries 0.0 0.0 0.0  
Deferred income taxes 90.2 84.9 0.0  
Other Assets, Noncurrent 599.9 411.1 10.5  
Long-term receivables—affiliates 0.0 0.0    
Intangible Assets, Net 647.7 677.0 112.0  
Goodwill 1,153.1 1,183.9 747.1  
Total assets 8,745.6 8,378.9 2,352.7  
Current installments of long-term debt 12.2 12.2 12.2  
Accounts payable 456.4 576.6 101.7  
Intercompany payables 0.0 0.0 0.0  
Income taxes payable 13.9 6.1 0.0  
Accrued Liabilities, Current 266.8 221.3 172.8  
Total current liabilities 749.3 816.2 286.7  
Long-term Debt, Excluding Current Maturities 12.3 12.4 24.7  
Accrued pension liability 456.4 164.6 1.1  
Deferred income taxes 926.8 945.1 167.5  
Long-term payables—affiliates 985.1 979.7    
Other Liabilities, Noncurrent 69.2 61.1 60.8  
Total liabilities 3,199.1 2,979.1 540.8  
Common Stock, Value, Issued 15.1 14.6 14.6  
Additional Paid in Capital, Common Stock 4,750.5 4,789.6 1,232.3  
Accumulated other comprehensive loss (20.7) (31.7) (20.4)  
Retained Earnings (Accumulated Deficit) 801.6 627.3 585.4  
Total shareholders' equity 5,546.5 5,399.8 1,811.9  
Liabilities and Equity 8,745.6 8,378.9 2,352.7  
Eliminations        
Supplemental Guarantor Financial Information Balance Sheets [Line Items]        
Cash and cash equivalents 0.0 0.0 0.0 $ 0.0
Receivables, net 0.0 (3.7) 0.0  
Intercompany receivables (1,740.8) (1,169.2) (770.7)  
Income taxes receivable (0.6) (0.1)    
Inventories 0.0 0.0 0.0  
Current deferred income taxes   (2.7) 0.0  
Other Assets, Current (133.6) (121.8) (105.5)  
Total current assets (1,875.0) (1,297.5) (876.2)  
Property, Plant and Equipment, Net 0.0 0.0 0.0  
Investment in subsidiaries (9,691.0) (9,541.3) (1,811.9)  
Deferred income taxes (131.7) (144.6) (49.5)  
Other Assets, Noncurrent 0.0 0.0 0.0  
Long-term receivables—affiliates (2,492.8) (2,562.6)    
Intangible Assets, Net 0.0 0.0 0.0  
Goodwill 0.0 0.0 0.0  
Total assets (14,190.5) (13,546.0) (2,737.6)  
Current installments of long-term debt 0.0 0.0 0.0  
Accounts payable (2.1) (5.7) (3.3)  
Intercompany payables (1,740.8) (1,169.2) (770.7)  
Income taxes payable (0.6) (2.7) 0.0  
Accrued Liabilities, Current (133.4) (121.0) (102.2)  
Total current liabilities (1,876.9) (1,298.6) (876.2)  
Long-term Debt, Excluding Current Maturities 0.0 0.0 0.0  
Accrued pension liability 0.0 0.0 0.0  
Deferred income taxes (131.7) (144.7) (49.5)  
Long-term payables—affiliates (2,492.8) (2,562.6)    
Other Liabilities, Noncurrent 0.0 1.2 0.0  
Total liabilities (4,501.4) (4,004.7) (925.7)  
Common Stock, Value, Issued (15.1) (14.6) (14.6)  
Additional Paid in Capital, Common Stock (8,876.2) (8,935.7) (1,232.3)  
Accumulated other comprehensive loss 20.7 31.7 20.4  
Retained Earnings (Accumulated Deficit) (818.5) (622.7) (585.4)  
Total shareholders' equity (9,689.1) (9,541.3) (1,811.9)  
Liabilities and Equity $ (14,190.5) $ (13,546.0) $ (2,737.6)