Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Year	$ 24.9	$ 24.5	$ 24.8
Additions Charged to Costs and Expenses	0.1	5.0	10.9
Additions Charged to Other Accounts	0.0	0.0	0.0
Deductions	7.9	4.6	11.2
Balance at End of Year	17.1	24.9	24.5
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Year	18.6	17.3	22.2
Additions Charged to Costs and Expenses	8.9	1.5	1.0
Additions Charged to Other Accounts	0.0	0.4	0.6
Deductions	0.5	0.6	6.5
Balance at End of Year	$ 27.0	$ 18.6	$ 17.3