Income Taxes (Components Of Federal And State Income Taxes Included In The Consolidated Statements Of Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Current Income Taxes [Abstract]
Federal			$ 39,974	$ (6,318)
State			9,607	2,496
Deferred Income Taxes [Abstract]
Federal			50,110	82,788
State			21,829	19,769
Income Tax Expense	66,095	55,186	121,520	98,735
Deferred Investment Tax Credit			(218)	(213)
Total Income Taxes			121,302	98,522
Presented as Follows [Abstract]
Other Income			(218)	(213)
Income Tax Expense	$ 66,095	$ 55,186	$ 121,520	$ 98,735