Regulatory Matters (Narrative) (Details) $ in Millions	12 Months Ended
	Sep. 30, 2021 USD ($)
New York [Member]
Regulatory Matters [Line Items]
Approved Return on Equity	8.70%
Pennsylvania [Member]
Regulatory Matters [Line Items]
Proposed Base Rate Reduction	$ (7.7)
Proposed Refund To Customers From Over Collection Of OPEB Expenses	$ 50.0