Derivative Financial Instruments and Related Hedging Programs, Notional Quantity Table (Details)	Dec. 31, 2013 2014	Dec. 31, 2013 2015	Dec. 31, 2013 2016	Dec. 31, 2013 Not Designated as Hedging Instrument Hedges Relating to the Convertible Notes Bifurcated Conversion Feature	Dec. 31, 2013 Not Designated as Hedging Instrument Hedges Relating to the Convertible Notes Call Options	Dec. 31, 2013 Purchase Not Designated as Hedging Instrument Aluminum Fixed priced contracts mmlbs	Dec. 31, 2013 Purchase Not Designated as Hedging Instrument Aluminum Midwest premium swap contracts mmlbs	Dec. 31, 2013 Purchase Not Designated as Hedging Instrument Natural Gas Fixed priced contracts MMBTU	Dec. 31, 2013 Purchase Not Designated as Hedging Instrument Electricity Fixed priced contracts MWH	Dec. 31, 2013 Purchase Euro Not Designated as Hedging Instrument Foreign Currency Fixed priced contracts EUR (€)	Dec. 31, 2013 Purchase GBP Not Designated as Hedging Instrument Foreign Currency Fixed priced contracts GBP (£)
Summary of material derivative positions
Notional Amount of Contracts				3,638,303	3,638,303	64.4	60.1	6,240,000	394,200
Notional Amount of Contracts, Currency										€ 674,483	£ 44,106
Percentage of natural gas purchases for which the Company's exposure to fluctuations in gas prices have been reduced	82.00%	64.00%	6.00%