Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Sep. 30, 2013
Income Tax Disclosures [Line Items]
Deferred Tax Assets, Valuation Allowance	$ 31.3		$ 31.3		$ 31.0
Income tax expense (benefit)	70.9	31.1	137.5	72.7
Effective Income Tax Rate Reconciliation, Percent	35.10%	21.90%	35.10%	29.10%
Valuation Allowance, Deferred Tax Asset, Change in Amount		(18.7)
Deferred tax assets net of DTL	$ 601.1		$ 601.1		$ 617.6