Derivatives And Other Financial Instruments (Schedule Of Outstanding Forward Contracts That Were Entered Into Hedge Forecasted Transactions) (Details)	Mar. 31, 2012	Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Natural gas (million British thermal units)	18,540,000
Energy Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Energy contracts (electricity-megawatt hours)	100,578,295	100,578,295
Aluminum Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Aluminum contracts (kmt)	1,342	1,294