Energy Services Accounts Receivable Securitization Facility (Details) - USD ($)	6 Months Ended		9 Months Ended
	Oct. 31, 2016	Apr. 30, 2016	Jun. 30, 2016	Jun. 30, 2015
Energy Services
Accounts, Notes, Loans and Financing Receivable
Sale of trade receivables			$ 615,300,000	$ 873,400,000
Energy Services Funding Corporation
Accounts, Notes, Loans and Financing Receivable
Sale of undivided interests in its trade receivables to the commercial paper conduit			167,500,000	272,500,000
Outstanding balance of trade receivables			40,400,000	42,900,000
Outstanding balance of trade receivables sold			$ 0	$ 20,000,000
Maximum
Accounts, Notes, Loans and Financing Receivable
Receivables facility		$ 150,000,000
Forecast | Maximum
Accounts, Notes, Loans and Financing Receivable
Receivables facility	$ 75,000,000