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Contingencies (Details) (USD $)
|
3 Months Ended |
|
Mar. 31, 2015
|
Dec. 31, 2014
|
Jun. 30, 2015
|
| Applicability, Impact and Conclusion of Environmental Loss Contingencies [Abstract] |
|
|
|
| Accrual for environmental loss contingencies |
$ 32,800,000 |
$ 32,500,000 |
|
| Asset Retirement Obligation [Abstract] |
|
|
|
| Discounted asset retirement obligation |
729,200,000 |
771,600,000 |
|
| Loss Contingencies [Line Items] |
|
|
|
| Number of specified mineral processing wastes exempted from EPA rules |
20 |
|
|
| Unfavorable Regulatory Action [Member] |
|
|
|
| Loss Contingencies [Line Items] |
|
|
|
| Future capital expenditures |
150,000,000 |
|
|
| Asset retirement obligations, undiscounted |
|
1,700,000,000 |
|
| Asset Retirement Obligation |
|
543,000,000 |
|
| Amount of cash potentially held in the form of cash escrow or trust fund in the context of a settlement of government enforcement action |
630,000,000 |
|
|
| Brazilian Non Income Tax Proceedings [Member] |
|
|
|
| Loss Contingencies [Line Items] |
|
|
|
| Loss contingency, maximum potential liability estimate |
77,000,000 |
|
|
| Brazilian Non Income Tax Proceedings [Member] | PIS And Cofins Cases [Member] |
|
|
|
| Loss Contingencies [Line Items] |
|
|
|
| Loss contingency, maximum potential liability estimate |
48,000,000 |
|
|
| Plant City Trust [Member] |
|
|
|
| Restricted Cash and Investments, Noncurrent [Abstract] |
|
|
|
| Funds for asset retirement obligation |
|
189,200,000 |
|
| Increase in funds for asset retirement obligation |
|
7,000,000 |
|
| Bonnie Facility Trust [Member] |
|
|
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| Restricted Cash and Investments, Noncurrent [Abstract] |
|
|
|
| Funds for asset retirement obligation |
|
14,500,000 |
|
| Bonnie Facility Trust [Member] | Estimate [Member] |
|
|
|
| Restricted Cash and Investments, Noncurrent [Abstract] |
|
|
|
| Increase in funds for asset retirement obligation |
|
|
3,000,000 |
| C F Asset Retirement Obligations [Member] |
|
|
|
| Asset Retirement Obligation [Abstract] |
|
|
|
| Discounted asset retirement obligation |
|
$ 103,500,000 |
|