Retirement Plan And Other Post-Retirement Benefits (Components Of Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	$ 2,997		$ 3,961		$ 8,990		$ 11,884
Interest Cost	10,893		9,124		32,681		27,373
Expected Return on Plan Assets	(14,993)		(14,336)		(44,980)		(43,009)
Amortization of Prior Service Cost (Credit)	52		60		157		179
Amortization of Transition Amount	0		0		0		0
Amortization of Losses	9,002		13,194		27,005		39,582
Net Amortization and Deferral For Regulatory Purposes (Including Volumetric Adjustments)	456	[1]	(3,854)	[1]	10,591	[1]	(5,813)	[1]
Net Periodic Benefit Cost	8,407		8,149		34,444		30,196
Other Post-Retirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service Cost	735		1,176		2,204		3,529
Interest Cost	5,327		4,803		15,981		14,409
Expected Return on Plan Assets	(9,356)		(8,218)		(28,067)		(24,654)
Amortization of Prior Service Cost (Credit)	(534)		(534)		(1,604)		(1,604)
Amortization of Transition Amount	0		2		0		6
Amortization of Losses	661		5,223		1,984		15,669
Net Amortization and Deferral For Regulatory Purposes (Including Volumetric Adjustments)	5,325	[1]	2,393	[1]	19,314	[1]	11,555	[1]
Net Periodic Benefit Cost	$ 2,158		$ 4,845		$ 9,812		$ 18,910

[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.