Quarterly report pursuant to Section 13 or 15(d)

Inventories (Schedule Of Inventory) (Details)

v2.3.0.15
Inventories (Schedule Of Inventory) (Details) (USD $)
In Millions
Sep. 30, 2011
Dec. 31, 2010
Finished Goods $ 395.7 $ 198.0
Work-in Process 132.5 71.2
Total Inventory 528.2 269.2
U.S. Iron Ore [Member]
    
Finished Goods 235.4 101.1
Work-in Process 21.5 9.7
Total Inventory 256.9 110.8
Eastern Canadian Iron Ore [Member]
    
Finished Goods 101.1 43.5
Work-in Process 28.8 21.2
Total Inventory 129.9 64.7
North American Coal [Member]
    
Finished Goods 7.1 16.1
Work-in Process 65.9 19.8
Total Inventory 73.0 35.9
Asia Pacific Iron Ore [Member]
    
Finished Goods 37.5 34.7
Work-in Process 14.0 20.4
Total Inventory 51.5 55.1
Other Segment [Member]
    
Finished Goods 14.6 2.6
Work-in Process 2.3 0.1
Total Inventory $ 16.9 $ 2.7