Quarterly report pursuant to Section 13 or 15(d)

BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Investments In Unconsolidated Ventures) (Details)

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BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Investments In Unconsolidated Ventures) (Details) (USD $)
In Millions, unless otherwise specified
Sep. 30, 2014
Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]    
Investment $ 32.5 $ 30.8
Other Noncurrent Liabilities [Member] | Hibbing [Member]
   
Schedule of Equity Method Investments [Line Items]    
Investment   (3.9) [1]
Other Noncurrent Assets [Member] | Hibbing [Member]
   
Schedule of Equity Method Investments [Line Items]    
Ownership interest, equity method investment 23.00% [1]  
Investment 8.1 [1]  
Other Noncurrent Assets [Member] | Other Equity Investees [Member]
   
Schedule of Equity Method Investments [Line Items]    
Investment $ 24.4 $ 34.7
[1] At December 31, 2013, the classification for Hibbing was Other liabilities.