Goodwill (Schedule of Accumulated Impairment Losses) (Details) - USD ($) $ in Millions	Jun. 30, 2023	Sep. 30, 2022
Goodwill [Line Items]
Goodwill, gross	$ 1,222.8	$ 1,096.0
Goodwill, net	891.6	823.0
Americas
Goodwill [Line Items]
Goodwill, accumulated impairment losses	(331.2)	(273.0)
Goodwill, net	$ 151.5	$ 143.2