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BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES (Investments In Unconsolidated Ventures) (Details) (USD $)
In Millions, unless otherwise specified |
Jun. 30, 2013
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Dec. 31, 2012
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|---|---|---|---|---|---|---|---|---|
| Schedule of Equity Method Investments [Line Items] | Ìý | Ìý | ||||||
| Investment | $ 68.7 | $ 108.4 | ||||||
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Amapa [Member] | Investments In Ventures [Member]
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Ìý | Ìý | ||||||
| Schedule of Equity Method Investments [Line Items] | Ìý | Ìý | ||||||
| Ownership interest, equity method investment | 30.00% | Ìý | ||||||
| Total percentage of Amapa sold | 100.00% | Ìý | ||||||
| Investment | 29.4 | 101.9 | ||||||
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Cockatoo [Member] | Other Liabilities [Member]
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Ìý | Ìý | ||||||
| Schedule of Equity Method Investments [Line Items] | Ìý | Ìý | ||||||
| Ownership interest, equity method investment | 0.00% | [1] | 50.00% | [1] | ||||
| Investment | Ìý | (25.3) | [1] | |||||
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Hibbing [Member] | Investments In Ventures [Member]
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Ìý | Ìý | ||||||
| Schedule of Equity Method Investments [Line Items] | Ìý | Ìý | ||||||
| Investment | 6.4 | [2] | Ìý | |||||
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Hibbing [Member] | Other Liabilities [Member]
|
Ìý | Ìý | ||||||
| Schedule of Equity Method Investments [Line Items] | Ìý | Ìý | ||||||
| Investment | Ìý | (2.1) | [2] | |||||
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Other Equity Investees [Member] | Investments In Ventures [Member]
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Ìý | Ìý | ||||||
| Schedule of Equity Method Investments [Line Items] | Ìý | Ìý | ||||||
| Investment | $ 32.9 | $ 33.9 | ||||||
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Hibbing [Member] | Hibbing [Member] | Investments In Ventures [Member]
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Ìý | Ìý | ||||||
| Schedule of Equity Method Investments [Line Items] | Ìý | Ìý | ||||||
| Ownership interest, equity method investment | 23.00% | [2] | Ìý | |||||
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