Goodwill (Schedule of Accumulated Impairment Losses) (Details) - USD ($) $ in Millions	Mar. 31, 2026	Sep. 30, 2025
Goodwill [Line Items]
Goodwill, gross	$ 1,244.4	$ 1,238.6
Goodwill, accumulated impairment losses	(285.7)	(274.7)
Goodwill, net	958.7	963.9
Americas
Goodwill [Line Items]
Goodwill, accumulated impairment losses	(285.7)	(274.7)
Goodwill, net	$ 145.0	$ 143.5