Utility Regulatory Assets and Liabilities and Regulatory Matters (Details) (USD $) In Millions, unless otherwise specified				12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Apr. 30, 2013	Sep. 30, 2014 Minimum	Sep. 30, 2014 Maximum	Sep. 30, 2014 Removal Costs, Net Maximum	Sep. 30, 2014 Other Regulatory Assets (Liabilities) [Member] Minimum	Sep. 30, 2014 Other Regulatory Assets (Liabilities) [Member] Maximum
Regulatory Assets and Liabilities
Average remaining depreciable lives of the associated property				1 year	65 years
Unrealized gains (losses) on derivative financial instruments contracts	$ (1.4)	$ (1.7)
Fair value of electric utility electricity supply contracts	0.3	(4.8)
Period to recover costs related to other regulatory assets						5 years	1 year	20 years
Net Book Value of Asset Transferred			$ 2.6