Energy Services Accounts Receivable Securitization Facility (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Energy services accounts receivable securitization facility (Textual) [Abstract]
Receivables facility	$ 100
Energy Services [Member]
Energy services accounts receivable securitization facility (Textual) [Abstract]
Sale of trade receivables	766.1	674.4
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	224.0	266.5
Outstanding balance of trade receivables	58.2	41.0
Outstanding balance of trade receivables sold	$ 9.5	$ 10.0