Segment and Geographical Area Information, Textuals (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2011 | Sep. 30, 2010 | Sep. 30, 2011 | Sep. 30, 2010 | |
| Segment Reporting Information [Line Items] | ||||
| Charges relating to LTI programs and certain short-term incentive plans | $ 0.6 | $ 2.4 | ||
| Non-cash LIFO benefits (charges) | 7.1 | 2.0 | (12.8) | (6.2) |
| Unrealized (losses) gains on derivatives | (12.7) | 10.9 | (19.8) | (7.1) |
| Metal related gains(losses) on internal hedging activities | 2.3 | (0.8) | 11.6 | (2.7) |
Fabricated Products [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Environmental expenses included in operating results | 0.1 | 13.1 | 0.6 | 13.5 |
| Unrealized (losses) gains on derivatives | (2.0) | (2.4) | (0.6) | (5.2) |
All Other [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Unrealized (losses) gains on derivatives | $ (14.8) | $ 17.1 | $ (21.4) | $ 1.1 |
Anglesey Aluminum Limited [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Ownership holding in Anglesey | 49.00% | 49.00% | ||
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- Definition Internal hedging gain loss metal.
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- Definition The charge against earnings in the period for known or estimated future costs arising from requirements to perform environmental remediation activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The change in the inventory reserve representing the cumulative difference in cost between the first in, first out and the last in, first out inventory valuation methods, which change has been reflected in the statement of income during the period. 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.
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- Definition The amount of a reclassification adjustment made to prior period financial statement amounts.
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
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- Definition The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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