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Income Taxes (Details) (USD $)
In Millions, unless otherwise specified |
3 Months Ended | 3 Months Ended | ||||||
|---|---|---|---|---|---|---|---|---|
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Mar. 31, 2012
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Mar. 31, 2011
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Mar. 31, 2012
Lower Limit [Member]
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Mar. 31, 2012
Upper Limit [Member]
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Jul. 01, 2012
Scenario, Forecast [Member]
Iron Ore And Coal Mining Profits [Member]
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Mar. 31, 2012
United States [Member]
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Mar. 31, 2012
Canada [Member]
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Mar. 31, 2012
Australia [Member]
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| Income tax provision | $ (210.8) | $ 142.2 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Effective income tax rate | (112.40%) | 25.30% | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Effective income tax rate before discrete items | 23.20% | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| U.S. statutory tax rate | 35.00% | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Increased valuation allowance against deferred tax assets | 51.8 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Expected tax rate | Ìý | Ìý | Ìý | Ìý | 22.50% | Ìý | Ìý | Ìý |
| Unrecognized tax benefits | 78.5 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Change in unrecognized tax benefits | Ìý | Ìý | 27.2 | 29.5 | Ìý | Ìý | Ìý | Ìý |
| Additional accrued interest relating to unrecognized tax benefits | 0.1 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Effect of MRRT, increase in effective tax rate each year over the life of mines | Ìý | Ìý | 3.00% | 4.00% | Ìý | Ìý | Ìý | Ìý |
| Tax years that remain subject to examination | Ìý | Ìý | Ìý | Ìý | Ìý | 2009 and forward | 2005 and forward | 2007 and forward |
| Cost to settle audit | 23.9 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Net deferred tax assets | 314.7 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Increase to the balance of deferred tax assets resulting from settlements with MRRT | 334.6 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Valuation allowance | $ 19.9 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| X | ||||||||||
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- Definition
Cost to settle audit No definition available.
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- Definition
An entity's expected tax rate for the remainder of the current year before discrete items No definition available.
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- Definition
Effect of MRRT, increase in effective tax rate each year over the life of mines No definition available.
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| X | ||||||||||
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- Definition
Expected Tax Rate No definition available.
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- Definition
Tax years that remain subject to examination No definition available.
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- Definition
The component of income tax expense for the period representing amounts of income taxes paid or payable (or refundable) for the period for all income tax obligations as determined by applying the provisions of relevant enacted tax laws to relevant amounts of taxable Income or Loss from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The aggregate tax effects as of the balance sheet date of all future tax deductions arising from temporary differences between tax basis and generally accepted accounting principles basis recognition of assets, liabilities, revenues and expenses, which can only be deducted for tax purposes when permitted under enacted tax laws; net of deducting the allocated valuation allowance, if any, to reduce such amount to net realizable value. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The domestic federal statutory tax rate applicable under enacted tax laws to the Company's pretax income from continuing operations for the period. The "statutory" tax rate is the regular tax rate if there are alternative tax systems. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The gross amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns as of the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The gross amount of increases in unrecognized tax benefits resulting from settlements with taxing authorities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
This element represents the amount of interest expense accrued as of the date of the statement of financial position for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The net amount of all increases and decreases in unrecognized tax benefits for the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The amount of the valuation allowance recorded as of the balance sheet date pertaining to the specified deferred tax asset for which an assessment was made that it is more likely than not that all or a portion of such deferred tax asset will not be realized through related deductions on future tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The amount of the change in the period in the valuation allowance for a specified deferred tax asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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