Annual report pursuant to Section 13 and 15(d)

RELATED PARTIES (Narrative) (Details)

v2.4.0.8
RELATED PARTIES (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2002
Segment Reporting Information [Line Items]      
Due from Related Parties, Current $ 132.0 $ 149.8  
Due to Related Parties, Current 25.1 20.2  
U.S. Iron Ore [Member]
     
Segment Reporting Information [Line Items]      
Number Of Mines 5    
Eastern Canadian Iron Ore [Member]
     
Segment Reporting Information [Line Items]      
Number Of Mines 2    
Joint Venture Partners [Member] | U.S. Iron Ore [Member]
     
Segment Reporting Information [Line Items]      
Number Of Mines 3    
Joint Venture Partners [Member] | Eastern Canadian Iron Ore [Member]
     
Segment Reporting Information [Line Items]      
Number Of Mines 1    
Empire [Member]
     
Segment Reporting Information [Line Items]      
Accounts, Notes, Loans and Financing Receivable, Net, Noncurrent 11.3 19.3 120.0
Loans Receivable, Fair Value Disclosure $ 11.9 $ 21.3  
Fair Value Assumptions, Risk Free Interest Rate 1.28% 2.85%  
Prior [Member] | Empire [Member]
     
Segment Reporting Information [Line Items]      
Ownership interest, equity method investment     46.70%