Intangible Assets (Acquired Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets, gross	$ 720.5	$ 706.9
Accumulated amortization and impairment	(299.8)	(271.1)
Intangible assets, net	420.7	435.8
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	669.3	654.7
Accumulated amortization	(288.9)	(259.9)
Finite-lived intangible assets, net	380.4	394.8
Trade names and trademarks
Acquired Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets, gross	51.2	52.2
Accumulated impairment	(10.9)	(11.2)
Indefinite-lived intangible assets, net	40.3	41.0
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	552.0	538.0
Accumulated amortization	(234.7)	(209.9)
Finite-lived intangible assets, net	317.3	328.1
Patents and technology
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	36.8	39.1
Accumulated amortization	(16.9)	(16.3)
Finite-lived intangible assets, net	19.9	22.8
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	80.5	77.6
Accumulated amortization	(37.3)	(33.7)
Finite-lived intangible assets, net	$ 43.2	$ 43.9