ÐÇ¿Õ´«Ã½

Quarterly report pursuant to Section 13 or 15(d)

Segment Reporting (Summary Of Assets By Segment) (Details)

v2.4.0.6
Segment Reporting (Summary Of Assets By Segment) (Details) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2012
Dec. 31, 2011
Segment Reporting Information [Line Items] Ìý Ìý
Total assets $ 14,893.3 $ 14,541.7
Total Segment Assets [Member]
Ìý Ìý
Segment Reporting Information [Line Items] Ìý Ìý
Total assets 14,585.3 14,008.1
U.S. Iron Ore [Member]
Ìý Ìý
Segment Reporting Information [Line Items] Ìý Ìý
Total assets 1,758.9 1,691.8
Eastern Canadian Iron Ore [Member]
Ìý Ìý
Segment Reporting Information [Line Items] Ìý Ìý
Total assets 8,008.0 7,973.1
North American Coal [Member]
Ìý Ìý
Segment Reporting Information [Line Items] Ìý Ìý
Total assets 1,948.3 1,814.4
Asia Pacific Iron Ore [Member]
Ìý Ìý
Segment Reporting Information [Line Items] Ìý Ìý
Total assets 1,885.5 1,511.2
Other Segment [Member]
Ìý Ìý
Segment Reporting Information [Line Items] Ìý Ìý
Total assets 984.6 1,017.6
Corporate [Member]
Ìý Ìý
Segment Reporting Information [Line Items] Ìý Ìý
Total assets $ 308.0 $ 533.6