Goodwill (Schedule of Accumulated Impairment Losses) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Goodwill [Line Items]
Goodwill, gross	$ 1,199.8	$ 1,158.4	$ 1,096.0
Goodwill, net	905.1	861.7	823.0
Americas
Goodwill [Line Items]
Accumulated impairment losses	(294.7)	(296.7)	(273.0)
Goodwill, net	$ 146.3	$ 146.6	$ 143.2