Annual report pursuant to Section 13 and 15(d)

Segment Reporting (Schedule Of Segment Reporting Information, By Segment) (Details)

v2.4.0.6
Segment Reporting (Schedule Of Segment Reporting Information, By Segment) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 9 Months Ended 12 Months Ended
Dec. 31, 2011
Sep. 30, 2011
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2010
Sep. 30, 2010
Jun. 30, 2010
Mar. 31, 2010
Sep. 30, 2011
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Percentage of revenues from product sales and services                   100.00% 100.00% 100.00%
Revenues from product sales and services $ 1,662.5 $ 2,142.8 $ 1,805.8 $ 1,183.2 $ 1,424.1 $ 1,346.0 $ 1,184.3 $ 727.7   $ 6,794.3 $ 4,682.1 $ 2,342.0
Sales margin 496.2 861.3 731.6 599.5 483.5 477.3 415.2 150.5   2,688.6 1,526.5 311.7
Other operating expense                   (340.0) (256.3) (75.6)
Other income (expense)                   (107.1) 32.8 60.4
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES AND EQUITY INCOME (LOSS) FROM VENTURES                 16.1 2,241.5 1,303.0 296.5
Depreciation, depletion and amortization                   426.9 322.3 236.6
Capital additions                   960.9 275.8 168.2
TOTAL ASSETS 14,541.7       7,778.2         14,541.7 7,778.2  
Operating Segments [Member]
                       
TOTAL ASSETS 14,008.1       6,243.6         14,008.1 6,243.6  
U.S. Iron Ore [Member]
                       
Percentage of revenues from product sales and services                   52.00% 52.00% 52.00%
Revenues from product sales and services                   3,509.9 2,443.7 1,211.6
Sales margin                   1,679.3 788.4 213.2
Depreciation, depletion and amortization                   86.2 61.7 67.4
Capital additions                   191.4 84.7 42.6
TOTAL ASSETS 1,691.8       1,537.1         1,691.8 1,537.1  
Eastern Canadian Iron Ore [Member]
                       
Percentage of revenues from product sales and services                   17.00% 10.00% 10.00%
Revenues from product sales and services                   1,178.1 477.7 236.2
Sales margin                   290.9 133.6 62.3
Depreciation, depletion and amortization                   124.6 41.9 6.9
Capital additions                   303.1 18.8  
TOTAL ASSETS 7,973.1       629.6         7,973.1 629.6  
North American Coal [Member]
                       
Percentage of revenues from product sales and services                   8.00% 9.00% 9.00%
Revenues from product sales and services                   512.1 438.2 207.2
Sales margin                   (58.4) (28.6) (71.9)
Depreciation, depletion and amortization                   86.5 60.4 38.2
Capital additions                   181.0 89.5 20.8
TOTAL ASSETS 1,814.4       1,623.8         1,814.4 1,623.8  
Asia Pacific Iron Ore [Member]
                       
Percentage of revenues from product sales and services                   20.00% 24.00% 23.00%
Revenues from product sales and services                   1,363.5 1,123.9 542.1
Sales margin                   699.5 566.2 87.2
Depreciation, depletion and amortization                   100.9 133.9 110.6
Capital additions                   262.0 53.6 96.2
TOTAL ASSETS 1,511.2       1,195.3         1,511.2 1,195.3  
Other Segment [Member]
                       
Percentage of revenues from product sales and services                   3.00% 4.00% 6.00%
Revenues from product sales and services                   230.7 198.6 144.9
Sales margin                   77.3 66.9 20.9
Depreciation, depletion and amortization                   28.7 24.4 13.5
Capital additions                   23.4 29.2 8.6
TOTAL ASSETS 1,017.6       1,257.8         1,017.6 1,257.8  
Material Reconciling Items [Member]
                       
TOTAL ASSETS $ 533.6       $ 1,534.6         $ 533.6 $ 1,534.6