Energy Services Accounts Receivable Securitization Facility - Trade Receivables Transferred and Sold (Details) - ESFC - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2017
Accounts, Notes, Loans and Financing Receivable
Trade receivables transferred to ESFC during the period	$ 1,051.7	$ 848.3
ESFC trade receivables sold to the bank during the period	176.0	186.0
ESFC trade receivables - end of period	58.3	51.6	$ 44.8
Outstanding balance of trade receivables sold	$ 0.0	$ 30.0	$ 39.0