Intangible Assets and Goodwill Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 571.1	$ 585.4
Accumulated amortization on intangible assets	(178.4)	(174.2)
Indefinite and Finite Lived Intangible Assets, Gross	698.3	715.7
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	0.2	0.2
Accumulated amortization on intangible assets	(0.1)	(0.1)
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	448.1	459.5
Accumulated amortization on intangible assets	(104.0)	(100.7)
Technology-Based Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	75.1	77.9
Accumulated amortization on intangible assets	(34.0)	(33.3)
Computer Software, Intangible Asset [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	47.3	47.4
Accumulated amortization on intangible assets	(40.0)	(39.8)
Other Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	0.4	0.4
Accumulated amortization on intangible assets	(0.3)	(0.3)
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	$ 127.2	$ 130.3
Minimum
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years
Maximum
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	21 years