Annual report pursuant to Section 13 and 15(d)

INVENTORIES (Narrative) (Details)

v2.4.0.8
INVENTORIES (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
U.S. Iron Ore [Member]
      
Inventory [Line Items]      
Inventory, LIFO Reserve $ 115.3 $ 122.2  
Effect of LIFO Inventory Liquidation on Income 7.4    
Increase in Inventories due to build up of LIFO layers   47.5  
Eastern Canadian Iron Ore [Member]
      
Inventory [Line Items]      
Inventory, LIFO Reserve   27.7  
Cost of Sales [Member] | Eastern Canadian Iron Ore [Member]
      
Inventory [Line Items]      
Effect of LIFO Inventory Liquidation on Income   (7.0)  
Inventory Write-down   0  
Cost of Sales [Member] | North American Coal [Member]
      
Inventory [Line Items]      
Inventory Write-down 11.1 24.4 6.6
Pellets [Member] | Wabush [Member] | Cost of Sales [Member]
      
Inventory [Line Items]      
Inventory Write-down 11.1    
Unsaleable Inventory Impairment Charge 10.6    
Concentrate [Member] | Cost of Sales [Member] | Eastern Canadian Iron Ore [Member]
      
Inventory [Line Items]      
Inventory Write-down 13.2    
Concentrate [Member] | Wabush [Member] | Cost of Sales [Member]
      
Inventory [Line Items]      
Unsaleable Inventory Impairment Charge $ 7.9