Energy Services Accounts Receivable Securitization Facility - Trade Receivables Transferred and Sold (Details) - ESFC - USD ($)		6 Months Ended
		Mar. 31, 2017	Mar. 31, 2016	Sep. 30, 2016
Accounts, Notes, Loans and Financing Receivable
Trade receivables transferred to ESFC during the period		$ 633,700,000	$ 468,000,000
ESFC trade receivables sold to the bank during the period		151,000,000	167,500,000
ESFC trade receivables - end of period	[1]	85,300,000	55,300,000	$ 35,700,000
Outstanding balance of trade receivables sold		$ 0	$ 4,000,000	$ 25,500,000

[1] At March 31, 2017, no ESFC trade receivables were sold to the bank. At September 30, 2016 and March 31, 2016, the amounts of ESFC trade receivables sold to the bank were $25.5 and $4.0, respectively, and are reflected as “Short-term borrowings” on the Condensed Consolidated Balance Sheets.