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Segment Reporting (Schedule Of Segment Reporting Information, By Segment) (Detail) (USD $)
In Millions, unless otherwise specified |
3 Months Ended | 6 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
|
Jun. 30, 2012
|
Jun. 30, 2011
|
Jun. 30, 2012
|
Jun. 30, 2011
|
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| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | ||||||
| Revenues from product sales and services | $ 1,626.0 | $ 1,805.8 | $ 2,890.7 | $ 2,989.0 | ||||||
| Sales margin | 449.3 | 731.6 | 752.8 | 1,331.1 | ||||||
| Other operating expense | (84.0) | (113.8) | (156.4) | (171.2) | ||||||
| Depreciation, depletion and amortization | 132.1 | 106.8 | 249.4 | 186.6 | ||||||
| Other income (expense) | (47.6) | (28.0) | (91.1) | (7.1) | ||||||
| Capital additions | 266.1 | [1] | 206.4 | [1] | 619.5 | [1] | 297.4 | [1] | ||
| Income from continuing operations before income taxes and equity loss from ventures | 317.7 | 589.8 | 505.3 | 1,152.8 | ||||||
| Revenues from product sales and services for reportable segments, percent | 100.00% | 100.00% | 100.00% | 100.00% | ||||||
|
U.S. Iron Ore [Member]
|
Ìý | Ìý | Ìý | Ìý | ||||||
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | ||||||
| Revenues from product sales and services | 705.0 | 885.2 | 1,146.7 | 1,395.3 | ||||||
| Sales margin | 286.1 | 441.1 | 452.9 | 802.4 | ||||||
| Depreciation, depletion and amortization | 23.8 | 22.2 | 47.0 | 39.5 | ||||||
| Capital additions | 28.1 | [1] | 55.7 | [1] | 62.9 | [1] | 87.3 | [1] | ||
| Revenues from product sales and services for reportable segments, percent | 43.00% | 49.00% | 40.00% | 47.00% | ||||||
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Eastern Canadian Iron Ore [Member]
|
Ìý | Ìý | Ìý | Ìý | ||||||
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | ||||||
| Revenues from product sales and services | 303.9 | 297.6 | 524.6 | 424.9 | ||||||
| Sales margin | 11.7 | 68.0 | (2.6) | 102.5 | ||||||
| Depreciation, depletion and amortization | 38.6 | 31.5 | 76.5 | 41.3 | ||||||
| Capital additions | 177.3 | [1] | 60.7 | [1] | 307.9 | [1] | 64.2 | [1] | ||
| Revenues from product sales and services for reportable segments, percent | 19.00% | 16.00% | 18.00% | 14.00% | ||||||
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North American Coal [Member]
|
Ìý | Ìý | Ìý | Ìý | ||||||
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | ||||||
| Revenues from product sales and services | 209.2 | 159.7 | 399.2 | 324.7 | ||||||
| Sales margin | (9.6) | (14.8) | 5.0 | (17.7) | ||||||
| Depreciation, depletion and amortization | 24.3 | 20.8 | 44.4 | 42.4 | ||||||
| Capital additions | 32.7 | [1] | 28.5 | [1] | 71.8 | [1] | 56.0 | [1] | ||
| Revenues from product sales and services for reportable segments, percent | 13.00% | 9.00% | 14.00% | 11.00% | ||||||
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Asia Pacific Iron Ore [Member]
|
Ìý | Ìý | Ìý | Ìý | ||||||
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | ||||||
| Revenues from product sales and services | 361.3 | 381.6 | 721.1 | 727.0 | ||||||
| Sales margin | 146.8 | 205.0 | 271.9 | 400.8 | ||||||
| Depreciation, depletion and amortization | 39.8 | 24.9 | 69.8 | 48.9 | ||||||
| Capital additions | 16.9 | [1] | 58.0 | [1] | 126.2 | [1] | 83.3 | [1] | ||
| Revenues from product sales and services for reportable segments, percent | 22.00% | 21.00% | 25.00% | 24.00% | ||||||
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Other Segment [Member]
|
Ìý | Ìý | Ìý | Ìý | ||||||
| Segment Reporting Information [Line Items] | Ìý | Ìý | Ìý | Ìý | ||||||
| Revenues from product sales and services | 46.6 | 81.7 | 99.1 | 117.1 | ||||||
| Sales margin | 14.3 | 32.3 | 25.6 | 43.1 | ||||||
| Depreciation, depletion and amortization | 5.6 | 7.4 | 11.7 | 14.5 | ||||||
| Capital additions | $ 11.1 | [1] | $ 3.5 | [1] | $ 50.7 | [1] | $ 6.6 | [1] | ||
| Revenues from product sales and services for reportable segments, percent | 3.00% | 5.00% | 3.00% | 4.00% | ||||||
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