Income Taxes (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Current expense (benefit):
Federal	$ (10.4)	$ 24.4	$ 60.5
State	11.2	14.5	20.4
Foreign	18.8	15.0	25.8
Investment tax credit	(2.9)	(5.8)	(1.7)
Total current expense	16.7	48.1	105.0
Deferred expense (benefit):
Federal	76.2	79.3	54.5
State	5.2	2.4	6.4
Foreign	1.8	1.4	2.1
Investment tax credit amortization	(0.3)	(0.4)	(0.4)
Total deferred expense	82.9	82.7	62.6
Total income tax expense	$ 99.6	$ 130.8	$ 167.6