Regulatory Matters (Narrative) (Details) $ in Millions	12 Months Ended
	Sep. 30, 2019 USD ($)
Regulatory Matters [Line Items]
Approved Return on Equity	8.70%
Supply Corporation [Member]
Regulatory Matters [Line Items]
Proposed Annual Cost of Service	$ 295.4
Proposed Rate Base	$ 970.8
Proposed Return on Equity	15.00%