Goodwill and Intangible Assets Intangible Assets (Details) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2016	Sep. 30, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 584.6	$ 480.2
Finite-Lived Intangible Assets, Accumulated Amortization	166.3	144.8
Indefinite and Finite Lived Intangible Assets, Gross	714.7	604.4
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	0.2	0.2
Finite-Lived Intangible Assets, Accumulated Amortization	0.1	0.1
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	459.7	374.0
Finite-Lived Intangible Assets, Accumulated Amortization	94.6	78.7
Technology-Based Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	78.5	62.3
Finite-Lived Intangible Assets, Accumulated Amortization	32.0	28.0
Computer Software, Intangible Asset [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	45.8	43.3
Finite-Lived Intangible Assets, Accumulated Amortization	39.3	37.7
Other Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	0.4	0.4
Finite-Lived Intangible Assets, Accumulated Amortization	0.3	0.3
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	$ 130.1	$ 124.2
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	22 years