Intangible Assets (Acquired Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets, gross	$ 658.1	$ 663.3
Accumulated amortization and impairment	(238.6)	(224.8)
Intangible assets, net	419.5	438.5
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	601.9	598.5
Accumulated amortization	(226.5)	(211.2)
Finite-lived intangible assets, net	375.4	387.3
Trade names and trademarks
Acquired Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets, gross	56.2	64.8
Accumulated impairment	(12.1)	(13.6)
Indefinite-lived intangible assets, net	44.1	51.2
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	487.9	491.9
Accumulated amortization	(179.8)	(165.5)
Finite-lived intangible assets, net	308.1	326.4
Patents and technology
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	39.0	34.0
Accumulated amortization	(13.3)	(11.9)
Finite-lived intangible assets, net	25.7	22.1
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	75.0	72.6
Accumulated amortization	(33.4)	(33.8)
Finite-lived intangible assets, net	$ 41.6	$ 38.8