Financial Instruments (Schedule Of Derivatives And Hedged Items In Fair Value Hedging Relationships) (Details) $ in Thousands	3 Months Ended
	Dec. 31, 2019 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) on Derivative Recognized in the Consolidated Statement of Income	$ (732)
Amount of Gain or (Loss) on the Hedged Item Recognized in the Consolidated Statement of Income	732
Operating Revenues [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) on Derivative Recognized in the Consolidated Statement of Income	(732)
Amount of Gain or (Loss) on the Hedged Item Recognized in the Consolidated Statement of Income	732
Purchased Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) on Derivative Recognized in the Consolidated Statement of Income	0
Amount of Gain or (Loss) on the Hedged Item Recognized in the Consolidated Statement of Income	$ 0