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Forward Delivery Contracts and Financial Instruments (Details) (Forward Contracts [Member]) |  |  | 12 Months Ended
--- | --- | --- | ---
Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2011 Glencore Metal Agreement [Member] | Dec. 31, 2011 Glencore Sweep Agreement [Member] | Dec. 31, 2011 Glencore Nordural Metal Agreement [Member] | Dec. 31, 2011 Southwire Metal Agreement [Member] | Dec. 31, 2011 Billiton Tolling Agreement [Member] | Dec. 31, 2011 Glencore Toll Agreement 1 [Member] | Dec. 31, 2011 Glencore Toll Agreement 2 [Member]
Supply Commitment [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Customer |  |  | Glencore | [1] | Glencore | [2] | Glencore | Southwire | [3] | BHP Billiton | [4] | Glencore | [4] | Glencore | [4]
Volume |  |  | 20,400 mtpy | [1] | Surplus metal produced in the United States | [2] | 16,000mtpy | 240 million pounds per year (high conductivity molten aluminum) | [3] | 130,000 mtpy | [4] | 90,000 mtpy | [4] | 40,000 mtpy | [4]
Term |  |  | Through December 31, 2013 | [1] | Through December 31, 2012 | [2] | Through December 31, 2012 | Through December 31, 2013 | [3] | Through December 31, 2013 | [4] | Through July 31, 2016 | [4] | Through December 31, 2014 | [4]
Pricing |  |  | Variable, based on U.S. Midwest market | [1] | Variable, based on U.S. Midwest market | [2] | Variable, based on LME | Variable, based on U.S. Midwest market | [3] | LME-based | [4] | LME-based | [4] | LME-based | [4]
Other forward delivery contracts to sell primary aluminum (in metric tons) | 41,504 | 47,926 |  |  |  |  |  |  |  |  |  |  |  |  |
Fixed price commitments on these other forward delivery contracts (in metric tons) | 41 | 117 |  |  |  |  |  |  |  |  |  |  |  |  |
[1] | We account for the Glencore Metal Agreement as a derivative instrument under ASC 815. Under the Glencore Metal Agreement, pricing is based on then-current market prices, adjusted by a negotiated U.S. Midwest premium with a cap and a floor to the current U.S. Midwest premium.
[2] | The Glencore Sweep Agreement is for all metal produced in the U.S. in 2011, less existing sales agreements and high-purity metal sales. The term of the contract may be extended for one year upon mutual agreement.
[3] | The Southwire Metal Agreement contract contains termination rights in the event of a partial or full curtailment of the Hawesville facility.
[4] | Grundartangi's tolling revenues include a premium based on the EU import duty for primary aluminum.

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