Derivative Financial Instruments And Hedging (Notional Amounts Of Derivative Instruments Held) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011
Raw Materials [Member]
Derivative [Line Items]
Notional amount of derivatives, non-currency	33,080,000	124,900,000	1,395,470,000
Natural Gas [Member]
Derivative [Line Items]
Notional amount of derivatives, non-currency	1,164,000	1,990,000	3,885,000
Other Fuel [Member]
Derivative [Line Items]
Notional amount of derivatives, non-currency	4,757,000	10,627,000	12,966,000
Currency [Member]
Derivative [Line Items]
Notional amount of derivatives, currency	35,250	59,000	83,250