Schedule II: Valuation and Qualifying Accounts (Details) - SEC Schedule, 12-09, Allowance, Credit Loss - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 87.9	$ 94.2	$ 104.0
Additions Charged to Cost of Revenue	18.3	30.9	40.9
Deductions	(20.6)	(38.7)	(50.8)
Other and Foreign Exchange Impact	(0.8)	1.5	0.1
Balance at the End of the Year	$ 84.8	$ 87.9	$ 94.2