Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Effective income tax rate	20.90%	22.10%	22.90%	23.80%
Discrete Tax Benefits Net	$ 10.0	$ 6.0	$ 14.5	$ 4.6
Gross Unrecognized Tax Benefits	64.5		64.5		70.3
Net Impact on Effective Tax Rate of Unrecognized Tax Benefits, Tax Penalties, Accrued Interest and Offsetting Tax Assets	31.3		31.3
Reasonably possible amount of increase / (decrease) in unrecognized tax benefits for the next twelve months	9.3		9.3
Accrued interest and penalties for unrecognized tax benefits	$ 17.2		$ 17.2		$ 20.1