Energy Services Accounts Receivable Securitization Facility (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Energy services accounts receivable securitization facility (Additional Textual) [Abstract]
Receivables facility	$ 200
Energy Services Funding Corporation [Member]
Energy services accounts receivable securitization facility (Textual) [Abstract]
Sale of undivided interests in its trade receivables to the commercial paper conduit	266.5	68.0
Outstanding balance of trade receivables	41.0	50.9
Outstanding balance of trade receivables sold	10.0
Energy Services [Member]
Energy services accounts receivable securitization facility (Textual) [Abstract]
Sale of trade receivables	$ 674.4	$ 923.5