Financial Instruments (Schedule Of Derivatives And Hedged Items In Fair Value Hedging Relationships) (Details) $ in Thousands	9 Months Ended
	Jun. 30, 2015 USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) on the Derivative Recognized in the Consolidated Statement of Income	$ (9,646)
Amount of Gain or (Loss) on the Hedged Item Recognized in the Consolidated Statement of Income	9,646
Operating Revenues [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) on the Derivative Recognized in the Consolidated Statement of Income	(9,645)
Amount of Gain or (Loss) on the Hedged Item Recognized in the Consolidated Statement of Income	9,645
Purchased Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) on the Derivative Recognized in the Consolidated Statement of Income	(1)
Amount of Gain or (Loss) on the Hedged Item Recognized in the Consolidated Statement of Income	$ 1