Derivative Financial Instruments and Related Hedging Programs, Notional Quantity Table (Details) (EUR €)	Sep. 30, 2011 mmlbs
Aluminum Commodity [Member] | Call option purchase contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	12.2
Aluminum Commodity [Member] | Call option sales contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	12.2
Aluminum Commodity [Member] | Put option purchase contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	25.4
Aluminum Commodity [Member] | Put option sales contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	12.2
Aluminum Commodity [Member] | Fixed priced purchase contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	78.4
Aluminum Commodity [Member] | Fixed priced sales contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	6.0
Aluminum Commodity [Member] | Midwest premium swap contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	38.0	[1]
Natural Gas [Member] | Call option purchase contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	4,740,000	[2]
Natural Gas [Member] | Call option sales contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	690,000	[2]
Natural Gas [Member] | Put option purchase contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	690,000	[2]
Natural Gas [Member] | Put option sales contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	4,740,000	[2]
Natural Gas [Member] | Fixed priced purchase contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	1,920,000	[2]
Electricity [Member] | Fixed priced purchase contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts	219,600
Foreign Currency [Member] | Euros [Member] | Fixed priced purchase contracts [Member]
Summary of material derivative positions
Notional Amount of Contracts (Foreign Currency)	117,500
Hedges Relating to Notes [Member] | Bifurcated Conversion Feature [Member]
Summary of material derivative positions
Notional Amount of Contracts	3,621,608	[3]
Hedges Relating to Notes [Member] | Call Options [Member]
Summary of material derivative positions
Notional Amount of Contracts	3,621,608	[3]

[1] Regional premiums represent the premium over the London Metal Exchange price for primary aluminum which is incurred on the Company’s purchases of primary aluminum.

[2] As of September 30, 2011, the Company’s exposure to fluctuations in natural gas prices had been substantially reduced for approximately 96%, 74% and 46% of the expected natural gas purchases for the remainder of 2011, 2012 and 2013, respectively.

[3] The Bifurcated Conversion Feature represents the cash conversion feature of the Notes. To hedge against the potential cash outflows associated with the Bifurcated Conversion Feature, the Company purchased cash-settled Call Options. The Call Options have an exercise price equal to the conversion price of the Notes, subject to anti-dilution adjustments substantially similar to the anti-dilution adjustments for the Notes. The Call Options will expire upon the maturity of the Notes. Although the fair value of the Call Options is derived from a notional number of shares of the Company’s common stock, the Call Options may only be settled in cash.