Retirement Plan And Other Post-Retirement Benefits (Components Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands		3 Months Ended
		Dec. 31, 2022	Dec. 31, 2021
Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost		$ 1,297	$ 2,190
Interest Cost		10,629	5,707
Expected Return on Plan Assets		(16,648)	(13,074)
Amortization of Prior Service Cost (Credit)		109	134
Amortization of (Gains) Losses		(1,920)	6,601
Net Amortization and Deferral for Regulatory Purposes (Including Volumetric Adjustments)	[1]	5,378	4,420
Net Periodic Benefit Cost (Income)		(1,155)	5,978
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost		147	332
Interest Cost		3,912	2,267
Expected Return on Plan Assets		(6,403)	(7,340)
Amortization of Prior Service Cost (Credit)		(107)	(107)
Amortization of (Gains) Losses		(2,189)	(1,903)
Net Amortization and Deferral for Regulatory Purposes (Including Volumetric Adjustments)	[1]	3,820	6,246
Net Periodic Benefit Cost (Income)		$ (820)	$ (505)

[1] The Company’s policy is to record retirement plan and other post-retirement benefit costs in the Utility segment on a volumetric basis to reflect the fact that the Utility segment experiences higher throughput of natural gas in the winter months and lower throughput of natural gas in the summer months.