Supplemental Financial Information - Trade Receivables, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ (6.2)	$ (6.1)	$ (6.7)
Additions charged to costs and expenses	(18.4)	(16.3)	(16.3)
Deductions and other	23.2	16.2	16.9
Ending balance	(1.4)	(6.2)	(6.1)
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	(3.1)	(3.9)	(4.2)
Additions charged to costs and expenses	(0.3)	(0.3)	(1.1)
Deductions and other	2.1	1.1	1.4
Ending balance	(1.3)	(3.1)	(3.9)
Allowance for Cash Discounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	(3.1)	(2.2)	(2.5)
Additions charged to costs and expenses	(18.1)	(16.0)	(15.2)
Deductions and other	21.1	15.1	15.5
Ending balance	$ (0.1)	$ (3.1)	$ (2.2)