Quarterly report pursuant to Section 13 or 15(d)

Environmental and Mine Closure Obligations (Summary of Mine Closure Obligations) (Details)

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Environmental and Mine Closure Obligations (Summary of Mine Closure Obligations) (Details) (USD $)
In Millions
Jun. 30, 2011
Dec. 31, 2010
Environmental $ 13.7 $ 13.7
Mine closure 208.1 185.4
Total environmental and mine closure obligations 221.8 199.1
Less current portion 14.3 14.2
Long term environmental and mine closure obligations 207.5 184.9
Mine closure [Member] | LTV Steel Mining Company [Member]
   
Mine closure 17.6 17.1
U.S. Iron Ore [Member] | Owned or Operating Facilities [Member]
   
Mine closure 65.9 62.7
Eastern Canadian Iron Ore [Member] | Owned or Operating Facilities [Member]
   
Mine closure 66.2 49.3
Asia Pacific Iron Ore [Member] | Owned or Operating Facilities [Member]
   
Mine closure 16.7 15.4
North American Coal [Member] | Owned or Operating Facilities [Member]
   
Mine closure 35.0 34.7
Owned or Operating Facilities [Member] | Other Regions [Member]
   
Mine closure $ 6.7 $ 6.2