Retirement Benefits (Details 2) - USD ($) $ in Millions	Sep. 30, 2015	Sep. 30, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	$ 3.0	$ 4.0
Net actuarial loss	1,099.9	904.7
Total	1,102.9	908.7
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service cost (credit)	(22.9)	(31.9)
Net actuarial loss	17.1	32.6
Total	$ (5.8)	$ 0.7