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Fair Value Of Financial Instruments (Narrative) (Details) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | 12 Months Ended | 12 Months Ended | |||||||||
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Dec. 31, 2011
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Dec. 31, 2010
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Dec. 31, 2011
U.S. Iron Ore [Member]
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Dec. 31, 2010
U.S. Iron Ore [Member]
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Dec. 31, 2011
Empire [Member]
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Dec. 31, 2010
Empire [Member]
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Dec. 31, 2002
Empire [Member]
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Dec. 31, 2001
Empire [Member]
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Jun. 30, 2011
Significant Other Observable Inputs (Level 2) [Member]
U.S. Iron Ore [Member]
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Sep. 30, 2010
Significant Other Observable Inputs (Level 2) [Member]
U.S. Iron Ore [Member]
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Dec. 31, 2011
Significant Unobservable Inputs (Level 3) [Member]
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Sep. 30, 2011
Significant Unobservable Inputs (Level 3) [Member]
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| Fair Value, Assets And Liabilities Components [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Derivative Asset, Fair Value | $ 165.9 | $ 84.6 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | $ 20.0 | $ 161.8 | $ 83.8 | $ 49.0 |
| Interest rate on long term receivable | the higher of 9 percent or the prime rate plus 350 basis points | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Percent ownership interest | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | 46.70% | 46.70% | Ìý | Ìý | Ìý | Ìý |
| Percent ownership interest after assuming all mine liabilities | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | 79.00% | Ìý | Ìý | Ìý | Ìý | Ìý |
| Maximum deferred portion of supplemental payments | Ìý | Ìý | 22.3 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Long Term Accounts Notes And Loans Receivable Net Noncurrent | Ìý | Ìý | Ìý | Ìý | 26.5 | 32.8 | 120.0 | Ìý | Ìý | Ìý | Ìý | Ìý |
| Other non-current assets | 191.2 | 187.9 | 22.3 | 22.3 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Fair value of the receivable | Ìý | Ìý | $ 20.8 | $ 19.5 | $ 30.7 | $ 38.9 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Estimated credit-adjusted risk-free interest rate | Ìý | Ìý | 4.50% | Ìý | 2.58% | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
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- Details
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- Definition
This element represents the portion of the balance sheet assertion valued at fair value by the entity due to the entity from outside sources, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value. No definition available.
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- Definition
Maximum deferred portion of supplemental payments No definition available.
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- Definition
Risk Free Discount Rate No definition available.
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- Definition
The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR. No definition available.
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- Definition
Fair value of derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The aggregate of amounts due from customers or clients more than one year from the balance sheet date, for goods or services that have been delivered or sold in the normal course of business and an amount representing an agreement for an unconditional promise by the maker to pay the Company (holder) a definite sum of money at a future date more than one year from the balance sheet date, reduced to their estimated net realizable fair value by an allowance established by the Company of the amount it deems uncertain of collection and net of any write-downs taken for collection uncertainty on the part of the holder, respectively. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The parent entity's interest in net assets of the subsidiary, expressed as a percentage. No definition available.
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- Definition
Aggregate carrying amount, as of the balance sheet date, of noncurrent assets not separately disclosed in the balance sheet. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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