Retirement Plan And Other Post-Retirement Benefits (Schedule Of Benefit Obligations, Plan Assets And Funded Status) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Non-Current Assets	$ 36,512		$ 22,774
Amortization period	10 years
Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Obligation at Beginning of Period	946,305		1,070,744		949,777
Service Cost	11,987		15,846		14,202
Interest Cost	43,574		36,498		41,526
Plan Participants' Contributions	0		0		0
Retiree Drug Subsidy Receipts	0		0		0
Actuarial (Gain) Loss	53,887		(121,631)		120,338
Benefits Paid	(56,254)		(55,152)		(55,099)
Benefit Obligation at End of Period	999,499		946,305		1,070,744
Fair Value of Assets at Beginning of Period	799,307		701,676		601,719
Actual Return on Plan Assets	93,238		98,783		111,034
Employer Contributions	33,500		54,000		44,022
Fair Value of Assets at End of Period	869,791		799,307		701,676
Net Amount Recognized at End of Period (Funded Status)	(129,708)		(146,998)		(369,068)
Non-Current Liabilities	(129,708)		(146,998)		(369,068)
Non-Current Assets	0		0		0
Accumulated Benefit Obligation	940,068		886,942		986,223
Discount Rate	4.25%		4.75%		3.50%
Rate of Compensation Increase	4.75%		4.75%		4.75%
Expected Return on Plan Assets	(59,974)		(57,346)		(59,701)
Amortization of Prior Service Cost (Credit)	210		238		269
Amortization of Transition Amount	0		0		0
Recognition of Actuarial Loss	36,007	[1]	52,776	[1]	39,615	[1]
Net Amortization and Deferral for Regulatory Purposes	8,151		(10,406)		(6,900)
Net Periodic Benefit Cost	39,955		37,606		29,011
Discount Rate	4.75%		3.50%		4.50%
Expected Return on Plan Assets	8.00%		8.00%		8.25%
Rate of Compensation Increase	4.75%		4.75%		4.75%
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Obligation at Beginning of Period	460,634		561,263		485,452
Service Cost	2,939		4,705		4,016
Interest Cost	21,308		19,212		21,315
Plan Participants' Contributions	2,265		2,141		1,956
Retiree Drug Subsidy Receipts	1,419		1,526		1,528
Actuarial (Gain) Loss	1,087		(104,455)		71,708
Benefits Paid	(24,069)		(23,758)		(24,712)
Benefit Obligation at End of Period	465,583		460,634		561,263
Fair Value of Assets at Beginning of Period	472,392		414,134		351,990
Actual Return on Plan Assets	44,898		61,715		63,552
Employer Contributions	2,115		18,160		21,348
Fair Value of Assets at End of Period	497,601		472,392		414,134
Net Amount Recognized at End of Period (Funded Status)	32,018		11,758		(147,129)
Non-Current Liabilities	(4,494)		(11,016)		(147,129)
Non-Current Assets	36,512		22,774		0
Discount Rate	4.25%		4.75%		3.50%
Rate of Compensation Increase	4.75%		4.75%		4.75%
Expected Return on Plan Assets	(37,424)		(32,872)		(28,971)
Amortization of Prior Service Cost (Credit)	(2,138)		(2,138)		(2,138)
Amortization of Transition Amount	0		8		10
Recognition of Actuarial Loss	2,645	[1]	20,892	[1]	24,057	[1]
Net Amortization and Deferral for Regulatory Purposes	23,263		11,844		6,162
Net Periodic Benefit Cost	$ 10,593		$ 21,651		$ 24,451
Discount Rate	4.75%		3.50%		4.50%
Expected Return on Plan Assets	8.00%		8.00%		8.25%
Rate of Compensation Increase	4.75%		4.75%		4.75%

[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.