Goodwill and Acquired Intangible Assets (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2012 segments	Sep. 30, 2013
Number of reportable segments	2
Estimated aggregate future amortization expense for intangible assets, 2014		$ 48.9
Estimated aggregate future amortization expense for intangible assets, 2015		47.1
Estimated aggregate future amortization expense for intangible assets, 2016		39.7
Estimated aggregate future amortization expense for intangible assets, 2017		35.9
Estimated aggregate future amortization expense for intangible assets, 2018		31.9
Estimated aggregate future amortization expense for intangible assets, thereafter		69.6
Software Products [Member]
Goodwill and acquired intangible assets	768.1	979.3
Services [Member]
Goodwill and acquired intangible assets	$ 28.1	$ 62.9