Goodwill and Intangible Assets (Schedule Of Intangible Assets Subject To Amortization) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2017	Sep. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Total intangible assets, Gross Carrying Amount	$ 230.3	$ 213.9
Total intangible assets, Accumulated Amortization	(169.5)	(146.9)
Total intangible assets, Net Carrying Amount	$ 60.8	67.0
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	5 years
Gross Carrying Amount	$ 78.5	78.5
Accumulated Amortization	(62.3)	(57.7)
Net Carrying Amount	$ 16.2	20.8
Developed technology and other [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	5 years
Gross Carrying Amount	$ 150.2	133.8
Accumulated Amortization	(107.1)	(89.2)
Net Carrying Amount	$ 43.1	44.6
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period (Years)	3 years
Gross Carrying Amount	$ 1.6	1.6
Accumulated Amortization	(0.1)	0.0
Net Carrying Amount	$ 1.5	$ 1.6