Derivative Instruments Outstanding Trading Contracts (Details) (Forward Contracts [Member])	Sep. 30, 2014 gal
Sales [Member]
Derivative [Line Items]
Quantity In Gallons	1,260,000
Weighted Average Contract Prices	1.1118
Sales [Member] | Maximum [Member]
Derivative [Line Items]
Estimated Market Prices	1.1400
Sales [Member] | Minimum [Member]
Derivative [Line Items]
Estimated Market Prices	1.0838
Purchase [Member]
Derivative [Line Items]
Quantity In Gallons	1,261,000
Weighted Average Contract Prices	1.1107
Purchase [Member] | Maximum [Member]
Derivative [Line Items]
Estimated Market Prices	1.3176
Purchase [Member] | Minimum [Member]
Derivative [Line Items]
Estimated Market Prices	1.0913