Commitments and Contingent Liabilities (Details 1) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Accrual for Environmental Loss Contingencies [Abstract]
Other current liabilities	$ 14.6
Other liabilities	59.3
Total recorded environmental remediation costs	73.9	$ 61.4
Receivables	(1.8)
Other assets	(9.6)
Total recorded probable expected recoveries	(11.4)
Net environmental remediation costs	62.5
Discounted ongoing operating maintenance expenditures	51.6
Asset Retirement Obligation [Abstract]
Other current liabilities	0.7	0.4
Other liabilities	19.9	19.8
Total recorded conditional asset retirement obligations	20.6	20.2
Receivables	(0.1)	0.0
Other assets	(0.2)	(0.3)
Total recorded probable expected recoveries	(0.3)	(0.3)
Net conditional asset retirement obligations	$ 20.3	$ 19.9