Accounting For Derivative Instruments And Hedging Activities (Derivative Volumes Expected To Settle) (Details)	Dec. 31, 2011 2011 [Member] Diesel Fuel Derivatives [Member] Physical [Member]	Dec. 31, 2011 2011 [Member] Diesel Fuel Derivatives [Member] Financial [Member]	Dec. 31, 2011 2011 [Member] Physical [Member] Natural Gas Contracts (MMBTUs) [Member]	Sep. 30, 2011 2011 [Member] Physical [Member] Natural Gas Contracts (MMBTUs) [Member]	Dec. 31, 2011 2011 [Member] Financial [Member] Natural Gas Contracts (MMBTUs) [Member]	Sep. 30, 2011 2011 [Member] Financial [Member] Natural Gas Contracts (MMBTUs) [Member]	Dec. 31, 2012 2012 [Member] Diesel Fuel Derivatives [Member] Physical [Member]	Dec. 31, 2012 2012 [Member] Diesel Fuel Derivatives [Member] Financial [Member]	Dec. 31, 2012 2012 [Member] Physical [Member] Natural Gas Contracts (MMBTUs) [Member]	Sep. 30, 2011 2012 [Member] Physical [Member] Natural Gas Contracts (MMBTUs) [Member]	Dec. 31, 2012 2012 [Member] Financial [Member] Natural Gas Contracts (MMBTUs) [Member]	Sep. 30, 2011 2012 [Member] Financial [Member] Natural Gas Contracts (MMBTUs) [Member]	Dec. 31, 2013 2013 [Member] Diesel Fuel Derivatives [Member] Physical [Member]	Dec. 31, 2013 2013 [Member] Diesel Fuel Derivatives [Member] Financial [Member]	Dec. 31, 2013 2013 [Member] Physical [Member] Natural Gas Contracts (MMBTUs) [Member]	Sep. 30, 2011 2013 [Member] Physical [Member] Natural Gas Contracts (MMBTUs) [Member]	Dec. 31, 2013 2013 [Member] Financial [Member] Natural Gas Contracts (MMBTUs) [Member]	Sep. 30, 2011 2013 [Member] Financial [Member] Natural Gas Contracts (MMBTUs) [Member]	Dec. 31, 2014 2014 [Member] Diesel Fuel Derivatives [Member] Physical [Member]	Dec. 31, 2014 2014 [Member] Diesel Fuel Derivatives [Member] Financial [Member]	Dec. 31, 2014 2014 [Member] Physical [Member] Natural Gas Contracts (MMBTUs) [Member]	Sep. 30, 2011 2014 [Member] Physical [Member] Natural Gas Contracts (MMBTUs) [Member]	Dec. 31, 2014 2014 [Member] Financial [Member] Natural Gas Contracts (MMBTUs) [Member]	Sep. 30, 2011 2014 [Member] Financial [Member] Natural Gas Contracts (MMBTUs) [Member]	Sep. 30, 2011 Diesel Fuel Derivatives [Member] Physical [Member]	Sep. 30, 2011 Physical [Member] Natural Gas Contracts (MMBTUs) [Member]	Sep. 30, 2011 Diesel Fuel Derivatives [Member] Financial [Member]	Sep. 30, 2011 Financial [Member] Natural Gas Contracts (MMBTUs) [Member]
Derivatives, Fair Value [Line Items]
Derivative volumes	0	2,400,000	0	0.0	11,600,000	11.6	0	2,600,000	0	0.0	35,000,000	35.0	0	1,800,000	0	0.0	5,000,000	5.0	0	1,000,000	0	0.0	0	51.6	0	0	7,800,000	51,600,000