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Derivatives and Other Financial Instruments - Schedule of Gain or Loss on Hedged Items and Derivative Contracts (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 6 Months Ended
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Jun. 30, 2013 | Jun. 30, 2012 | Jun. 30, 2013 | Jun. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of gain/loss recognized in earnings related to the ineffective portion of hedging relationships | $ 0 | $ 1 | $ 0 | $ 10
Sales [Member] | Aluminum Contracts [Member] |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Amount of gain/loss recognized in earnings related to the ineffective portion of hedging relationships | $ 4 | $ 4 | $ 4 | $ 16

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- Definition Derivative instruments gain loss recognized in income related to ineffective portion. + References No definition available. + Details
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- Details
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