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, 2015	Sep. 30, 2014	Sep. 30, 2013
Defined Benefit Plan Disclosure [Line Items]
Non-Current Assets		$ 24,459	$ 36,512
Amortization period		10 years
Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit Obligation at Beginning of Period		$ 999,499	946,305	$ 1,070,744
Service Cost		12,047	11,987	15,846
Interest Cost		41,217	43,574	36,498
Plan Participants' Contributions		0	0	0
Retiree Drug Subsidy Receipts		0	0	0
Amendments	[1]	7,752	0	0
Actuarial (Gain) Loss		23,426	53,887	(121,631)
Benefits Paid		(57,751)	(56,254)	(55,152)
Benefit Obligation at End of Period		1,026,190	999,499	946,305
Fair Value of Assets at Beginning of Period		869,791	799,307	701,676
Actual Return on Plan Assets		(13,370)	93,238	98,783
Employer Contributions		36,200	33,500	54,000
Fair Value of Assets at End of Period		834,870	869,791	799,307
Net Amount Recognized at End of Period (Funded Status)		(191,320)	(129,708)	(146,998)
Non-Current Liabilities		(191,320)	(129,708)	(146,998)
Non-Current Assets		0	0	0
Accumulated Benefit Obligation		$ 968,984	$ 940,068	$ 886,942
Discount Rate		4.25%	4.25%	4.75%
Rate of Compensation Increase		4.75%	4.75%	4.75%
Expected Return on Plan Assets		$ (59,615)	$ (59,974)	$ (57,346)
Amortization of Prior Service Cost (Credit)		183	210	238
Amortization of Transition Amount		0	0	0
Recognition of Actuarial Loss	[2]	36,129	36,007	52,776
Net Amortization and Deferral for Regulatory Purposes		7,739	8,151	(10,406)
Net Periodic Benefit Cost		$ 37,700	$ 39,955	$ 37,606
Discount Rate		4.25%	4.75%	3.50%
Expected Return on Plan Assets		7.50%	8.00%	8.00%
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		$ 465,583	$ 460,634	$ 561,263
Service Cost		2,693	2,939	4,705
Interest Cost		19,285	21,308	19,212
Plan Participants' Contributions		2,242	2,265	2,141
Retiree Drug Subsidy Receipts		1,338	1,419	1,526
Amendments	[1]	0	0	0
Actuarial (Gain) Loss		(1,575)	1,087	(104,455)
Benefits Paid		(24,579)	(24,069)	(23,758)
Benefit Obligation at End of Period		464,987	465,583	460,634
Fair Value of Assets at Beginning of Period		497,601	472,392	414,134
Actual Return on Plan Assets		534	44,898	61,715
Employer Contributions		2,161	2,115	18,160
Fair Value of Assets at End of Period		477,959	497,601	472,392
Net Amount Recognized at End of Period (Funded Status)		12,972	32,018	11,758
Non-Current Liabilities		(11,487)	(4,494)	(11,016)
Non-Current Assets		$ 24,459	$ 36,512	$ 22,774
Discount Rate		4.50%	4.25%	4.75%
Rate of Compensation Increase		4.75%	4.75%	4.75%
Expected Return on Plan Assets		$ (34,089)	$ (37,424)	$ (32,872)
Amortization of Prior Service Cost (Credit)		(1,913)	(2,138)	(2,138)
Amortization of Transition Amount		0	0	8
Recognition of Actuarial Loss	[2]	4,148	2,645	20,892
Net Amortization and Deferral for Regulatory Purposes		20,322	23,263	11,844
Net Periodic Benefit Cost		$ 10,446	$ 10,593	$ 21,651
Discount Rate		4.25%	4.75%	3.50%
Expected Return on Plan Assets		7.00%	8.00%	8.00%
Rate of Compensation Increase		4.75%	4.75%	4.75%

[1] In fiscal 2015, the Company passed an amendment which updated the mortality table used in the Retirement Plan's definition of "actuarially equivalent" effective July 1, 2015. This increased the benefit obligation of the Retirement Plan.

[2] 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.