Energy Services Accounts Receivable Securitization Facility - Trade Receivables Transferred and Sold (Details) - ESFC - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Accounts, Notes, Loans and Financing Receivable
Trade receivables transferred to ESFC during the period	$ 884.8	$ 806.9
ESFC trade receivables sold to the bank during the period	41.0	128.0
ESFC trade receivables - end of period	117.0	99.6	$ 65.0
Outstanding balance of trade receivables sold	$ 0.0	$ 10.0	$ 2.0