Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Year	$ 24.5	$ 24.8	$ 22.2
Additions Charged to Costs and Expenses	5.0	10.9	8.1
Additions Charged to Other Accounts	0.0	0.0	0.0
Deductions	4.6	11.2	5.5
Balance at End of Year	24.9	24.5	24.8
Valuation Allowance of Deferred Tax Assets [Member]
Valuation and Qualifying Accounts
Balance at Beginning of Year	17.3	22.2	27.8
Additions Charged to Costs and Expenses	1.5	1.0	2.5
Additions Charged to Other Accounts	0.4	0.6	0.0
Deductions	0.6	6.5	8.1
Balance at End of Year	$ 18.6	$ 17.3	$ 22.2