Intangible Assets (Acquired Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets, gross	$ 578.7	$ 553.4
Accumulated amortization and impairment	(210.4)	(165.5)
Intangible assets, net	368.3	387.9
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	510.9	487.2
Accumulated amortization	(189.5)	(162.0)
Finite-lived intangible assets, net	321.4	325.2
Trade Names and Trademarks
Acquired Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets, gross	67.8	66.2
Accumulated impairment	(20.9)	(3.5)
Indefinite-lived intangible assets, net	46.9	62.7
Customer Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	424.1	400.6
Accumulated amortization	(142.3)	(118.2)
Finite-lived intangible assets, net	281.8	282.4
Patents and Technology
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	13.4	13.6
Accumulated amortization	(10.6)	(10.1)
Finite-lived intangible assets, net	2.8	3.5
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	73.4	73.0
Accumulated amortization	(36.6)	(33.7)
Finite-lived intangible assets, net	$ 36.8	$ 39.3