Goodwill (Schedule of Accumulated Impairment Losses) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Sep. 30, 2023
Goodwill [Line Items]
Goodwill, gross	$ 1,152.8	$ 1,158.4
Goodwill, net	883.2	861.7
Americas
Goodwill [Line Items]
Goodwill, accumulated impairment losses	(269.6)	(296.7)
Goodwill, net	$ 142.7	$ 146.6