Income Taxes (Components Of Federal And State Income Taxes Included In The Consolidated Statements Of Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Current Income Taxes [Abstract]
Federal			$ 7,995	$ 36,746
State			15,537	13,199
Deferred Income Taxes [Abstract]
Federal			(197,982)	13,242
State			(85,930)	(2,891)
Income Tax Expense (Benefit)	$ (116,030)	$ 5,136	(260,380)	60,296
Deferred Investment Tax Credit			(174)	(208)
Total Income Taxes			(260,554)	60,088
Presented as Follows [Abstract]
Other Income			(174)	(208)
Income Tax Expense (Benefit)	$ (116,030)	$ 5,136	$ (260,380)	$ 60,296