Risk Management Activities and Derivative Transactions Counterparty Credit Risk (Details)	Jun. 30, 2014 Customers	Sep. 30, 2013 Customers
Derivative
Number of active future commission merchants	2
Credit of Customers [Member]
Derivative
Number of customers that represent the percent of outstanding accounts receivable	3	3
Percent of total outstanding accounts receivables	27.00%	27.00%
Power Purchase Agreement
Derivative
Megawatts	440