Leases - Schedule of Additional Cash Flow Information Related to Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 172.6	$ 184.9	$ 188.3
Operating cash flows from finance leases	3.7	3.0	2.5
Financing cash flows from finance leases	32.4	28.9	23.7
Right-of-use assets obtained in exchange for new operating leases	130.9	90.1	96.6
Right-of-use assets obtained in exchange for new finance leases	$ 47.2	$ 26.6	$ 37.5