Income Taxes (Details 1) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Current expense (benefit):
Federal									$ 53.3	$ (10.4)	$ 24.4
State									25.1	11.2	14.5
Foreign									37.3	18.8	15.0
Investment tax credit									(1.6)	(2.9)	0
Total current expense									114.1	16.7	53.9
Deferred expense (benefit):
Federal									54.6	81.7	86.0
State									(0.7)	7.0	4.5
Foreign									(4.9)	1.8	1.4
Investment tax credit amortization									(0.3)	(0.3)	(0.4)
Total deferred expense									48.7	90.2	91.5
Total income tax expense	$ (13.2)	$ 5.1	$ 106.0	$ 64.9	$ (7.7)	$ 4.1	$ 77.2	$ 33.3	$ 162.8	$ 106.9	$ 145.4