Intangible Assets (Acquired Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets, gross	$ 672.4	$ 673.3
Accumulated amortization and impairment	(378.9)	(361.7)
Intangible assets, net	293.5	311.6
Intangible Asset, Acquired, Finite-Lived [Line Items]
Finite-lived intangible assets, gross	627.8	627.1
Accumulated amortization	(369.4)	(351.8)
Finite-lived intangible assets, net	258.4	275.3
Trade names and trademarks
Acquired Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets, gross	44.6	46.2
Accumulated impairment	(9.5)	(9.9)
Indefinite-lived intangible assets, net	35.1	36.3
Customer relationships
Intangible Asset, Acquired, Finite-Lived [Line Items]
Finite-lived intangible assets, gross	532.3	524.9
Accumulated amortization	(318.5)	(298.2)
Finite-lived intangible assets, net	213.8	226.7
Patents and technology
Intangible Asset, Acquired, Finite-Lived [Line Items]
Finite-lived intangible assets, gross	31.1	32.9
Accumulated amortization	(21.0)	(20.7)
Finite-lived intangible assets, net	10.1	12.2
Other
Intangible Asset, Acquired, Finite-Lived [Line Items]
Finite-lived intangible assets, gross	64.4	69.3
Accumulated amortization	(29.9)	(32.9)
Finite-lived intangible assets, net	$ 34.5	$ 36.4