Financial Instruments (Schedule Of Derivatives And Hedged Items In Fair Value Hedging Relationships) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) on the Derivative Recognized in the Consolidated Statement of Income	$ (13,141)
Amount of Gain or (Loss) on the Hedged Item Recognized in the Consolidated Statement of Income	13,141
Operating Revenues [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) on the Derivative Recognized in the Consolidated Statement of Income	(13,338)
Amount of Gain or (Loss) on the Hedged Item Recognized in the Consolidated Statement of Income	13,338
Purchased Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) on the Derivative Recognized in the Consolidated Statement of Income	197
Amount of Gain or (Loss) on the Hedged Item Recognized in the Consolidated Statement of Income	$ (197)