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Schedule Of Quantitative Information For Level 3 Derivative Contracts (Detail) (USD $) | 6 Months Ended
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Jun. 30, 2012
Interrelationship Of Future Aluminum And Oil Prices | Aluminum Contracts |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Derivative Assets, Fair Value | $ 3
Interrelationship Of Future Aluminum And Oil Prices | Aluminum Contracts | Minimum | Discounted Cash Flow |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Expected future aluminum prices | 1,828
Expected future oil prices | 88
Interrelationship Of Future Aluminum And Oil Prices | Aluminum Contracts | Maximum | Discounted Cash Flow |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Expected future aluminum prices | 2,390
Expected future oil prices | 91
Price Of Aluminum Beyond Forward Curve | Aluminum Contracts |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Derivative Liabilities, Fair Value | 523
Price Of Aluminum Beyond Forward Curve | Aluminum Contracts | Minimum | Discounted Cash Flow |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Price of aluminum beyond forward curve | 2,658,000,000
Maturity data of aluminum beyond forward curve | 2022
Price Of Aluminum Beyond Forward Curve | Aluminum Contracts | Maximum | Discounted Cash Flow |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Price of aluminum beyond forward curve | 2,896,000,000
Maturity data of aluminum beyond forward curve | 2027
Credit Spread Between Alcoa And Counterparty | Embedded Credit Derivative |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Derivative Liabilities, Fair Value | 39
Credit Spread Between Alcoa And Counterparty | Embedded Credit Derivative | Discounted Cash Flow |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Percentage of credit spread | 2.25%
Credit Spread Between Alcoa And Counterparty | Embedded Credit Derivative | Minimum | Discounted Cash Flow |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Percentage of credit spread | 2.03%
Credit Spread Between Alcoa And Counterparty | Embedded Credit Derivative | Maximum | Discounted Cash Flow |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Percentage of credit spread | 2.46%
Price Of Electricity Beyond Forward Curve | Energy Contracts |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Derivative Liabilities, Fair Value | 10
Price Of Electricity Beyond Forward Curve | Energy Contracts | Minimum | Discounted Cash Flow |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Price of electricity beyond forward curve | 77,000,000
Maturity date of electricity beyond forward curve | 2012
Price Of Electricity Beyond Forward Curve | Energy Contracts | Maximum | Discounted Cash Flow |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |
Price of electricity beyond forward curve | $ 170,000,000
Maturity date of electricity beyond forward curve | 2036

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