Retirement Plan And Other Post-Retirement Benefits (Schedule Of Benefit Obligations, Plan Assets And Funded Status) (Details) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Non-Current Assets		$ 196,597	$ 149,151
Amortization period		10 years
Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Obligation at Beginning of Period		$ 1,098,456	1,139,105	$ 1,097,625
Service Cost		8,758	9,865	9,318
Interest Cost		$ 22,827	$ 21,686	$ 29,930
Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]		Other Income (Deductions)	Other Income (Deductions)	Other Income (Deductions)
Plan Participants' Contributions		$ 0	$ 0	$ 0
Retiree Drug Subsidy Receipts		0	0	0
Actuarial (Gain) Loss		(251,173)	(8,141)	65,908
Benefits Paid		(65,040)	(64,059)	(63,676)
Benefit Obligation at End of Period		813,828	1,098,456	1,139,105
Fair Value of Assets at Beginning of Period		1,095,729	1,016,796	968,449
Actual Return on Plan Assets		(205,884)	122,992	87,402
Employer Contributions		20,400	20,000	24,621
Plan Participants' Contributions		0	0	0
Benefits Paid		(65,040)	(64,059)	(63,676)
Fair Value of Assets at End of Period		845,205	1,095,729	1,016,796
Net Amount Recognized at End of Period (Funded Status)		31,377	(2,727)	(122,309)
Non-Current Liabilities		0	(2,727)	(122,309)
Non-Current Assets		31,377	0	0
Accumulated Benefit Obligation		$ 793,555	$ 1,060,659	$ 1,096,427
Discount Rate		5.57%	2.75%	2.66%
Rate of Compensation Increase		4.60%	4.70%	4.70%
Expected Return on Plan Assets		$ (52,294)	$ (58,148)	$ (60,063)
Amortization of Prior Service Cost (Credit)		537	631	729
Recognition of Actuarial (Gain) Loss	[1]	26,405	36,814	39,384
Net Amortization and Deferral for Regulatory Purposes		16,854	14,063	5,359
Net Periodic Benefit Cost (Income)		$ 23,087	$ 24,911	$ 24,657
Effective Discount Rate for Benefit Obligations		2.75%	2.66%	3.15%
Effective Rate for Interest on Benefit Obligations		2.14%	1.96%	2.81%
Effective Discount Rate for Service Cost		2.95%	3.01%	3.31%
Effective Rate for Interest on Service Cost		2.70%	2.60%	3.12%
Expected Return on Plan Assets		5.20%	6.00%	6.40%
Rate of Compensation Increase		4.70%	4.70%	4.70%
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Obligation at Beginning of Period		$ 431,213	$ 476,722	$ 468,163
Service Cost		1,328	1,602	1,609
Interest Cost		$ 9,066	$ 9,303	$ 12,913
Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]		Other Income (Deductions)	Other Income (Deductions)	Other Income (Deductions)
Plan Participants' Contributions		$ 3,271	$ 3,216	$ 3,058
Retiree Drug Subsidy Receipts		312	1,244	1,411
Actuarial (Gain) Loss		(120,276)	(34,729)	16,396
Benefits Paid		(25,631)	(26,145)	(26,828)
Benefit Obligation at End of Period		299,283	431,213	476,722
Fair Value of Assets at Beginning of Period		575,565	547,885	524,127
Actual Return on Plan Assets		(94,849)	47,541	44,448
Employer Contributions		3,082	3,068	3,080
Plan Participants' Contributions		3,271	3,216	3,058
Benefits Paid		(25,631)	(26,145)	(26,828)
Fair Value of Assets at End of Period		461,438	575,565	547,885
Net Amount Recognized at End of Period (Funded Status)		162,155	144,352	71,163
Non-Current Liabilities		(3,065)	(4,799)	(4,872)
Non-Current Assets		$ 165,220	$ 149,151	$ 76,035
Discount Rate		5.56%	2.76%	2.71%
Rate of Compensation Increase		4.60%	4.70%	4.70%
Expected Return on Plan Assets		$ (29,359)	$ (28,964)	$ (29,232)
Amortization of Prior Service Cost (Credit)		(429)	(429)	(429)
Recognition of Actuarial (Gain) Loss	[1]	(7,610)	849	535
Net Amortization and Deferral for Regulatory Purposes		21,340	28,010	25,596
Net Periodic Benefit Cost (Income)		$ (5,664)	$ 10,371	$ 10,992
Effective Discount Rate for Benefit Obligations		2.76%	2.71%	3.17%
Effective Rate for Interest on Benefit Obligations		2.17%	2.01%	2.84%
Effective Discount Rate for Service Cost		3.00%	3.20%	3.39%
Effective Rate for Interest on Service Cost		2.93%	2.98%	3.30%
Expected Return on Plan Assets		5.20%	5.40%	5.70%
Rate of Compensation Increase		4.70%	4.70%	4.70%

[1] Distribution Corporation’s New York jurisdiction calculates the amortization of the actuarial loss on a vintage year basis over 10 years, as mandated by the NYPSC. All the other subsidiaries of the Company utilize the corridor approach.