Retirement Benefits (Details 2) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
Amounts included in accumulated other comprehensive loss, net of tax
Total	$ 1,226.0	$ 1,033.6
Pension Benefits [Member]
Amounts included in accumulated other comprehensive loss, net of tax
Prior service credit	(0.3)	(2.1)
Net actuarial loss	1,210.7	1,038.0
Net transition (benefit) obligation	(0.1)	(0.1)
Total	1,210.3	1,035.8
Other Postretirement Benefits [Member]
Amounts included in accumulated other comprehensive loss, net of tax
Prior service credit	(21.8)	(28.4)
Net actuarial loss	37.5	26.2
Net transition (benefit) obligation
Total	$ 15.7	$ (2.2)