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Derivatives And Other Financial Instruments - Additional Information (Detail) In Millions, unless otherwise specified | 6 Months Ended |  | 6 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Jun. 30, 2012 USD ($) Year MetricTon | Dec. 31, 2009 USD ($) | Dec. 31, 2009 CAD | Jun. 30, 2012 Six Year Natural Gas Supply Contract USD ($) | Jun. 30, 2012 Level 3 USD ($) | Jun. 30, 2012 Level 1 USD ($) | Dec. 31, 2011 Level 1 USD ($) | Jun. 30, 2012 Level 2 USD ($) | Dec. 31, 2011 Level 2 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |  |  |  |
Net unrealized loss on derivative contracts |  |  |  | $ 5 | $ 569 |  |  |  |
Other derivative contracts estimated term of quoted market prices, in years |  |  |  |  |  |  |  |  |
Supply contract duration |  |  |  | 6 years |  |  |  |  |
Amount of aluminum kmt designated as fair value hedges | 462 |  |  |  |  |  |  |  |
Face amount of debt the hedges effectively convert from fixed to floating through 2018 | 200 |  |  |  |  |  |  |  |
Contracts expiration date | September 2011 |  |  |  |  |  |  |  |
Forward contract to purchase to mitigate the foreign currency risk related to a Canadian-denominated loan due in 2014 |  | 57 | 58 |  |  |  |  |  |
Long-term debt, fair value |  |  |  |  |  | $ 8,679 | $ 8,576 | $ 595 | $ 698

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- Definition Aluminum futures designated as fair value hedges in kilo metric ton. + References No definition available. + Details
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- Definition The amount of foreign currency that the entity has contractually agreed, or for which it has the option, to buy or sell with respect to the contract being described. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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- Definition The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 21 -Paragraph 16, 20 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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- Definition This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. + References No definition available. + Details
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