Income Taxes (Details Textuals 1) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Income Taxes [Abstract]
Income Tax Expense (Benefit)	$ 99.9	$ 112.4	$ 82.2	$ 78.2	$ 84.5	$ 58.7	$ 70.9	$ 66.5	$ 372.7	$ 280.7	$ 195.1
Operating Loss Carryforwards [Line Items]
Unrecognized Tax Benefits	0.0				0.0				0.0	0.0	4.2	$ 14.1
Valuation allowance	(10.1)				(31.1)				(10.1)	(31.1)
Valuation Allowance, Deferred Tax Asset, Change in Amount	17.5
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions									0.0	4.2	2.4
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations									0.0	0.0	7.5
Income Tax Uncertainties [Abstract]
Interest expense related to unrecognized tax benefits										(2.2)	$ (2.8)
Total accrued interest expense related to unrecognized tax benefits	0.0								0.0
Accrued penalties on income taxes	0.0				$ 0.0				0.0	$ 0.0
NOL Carryforwards to Expire in Six to Ten Years [Member] | State [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Subject to Expiration	$ 19.8								$ 19.8