Basis of Presentation and Accounting Policies - Narrative (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023
Accounting Policies [Abstract]
Allowance for doubtful accounts	$ 19.3		$ 16.8
Antidilutive share-based compensation awards (in shares)	0.5	0.6
Capital expenditures in accounts payable or other current liabilities at period end	$ 20.5	$ 32.9
Outstanding purchase of common stock recorded in accounts payable	1.1	$ 0.8
Supplier finance program, obligation	$ 117.5		$ 126.7