Income Taxes (Schedule Of Income Tax Reconciliation By Applying Federal Income Tax Rate) (Details) - USD ($) $ in Thousands			12 Months Ended
		Oct. 01, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Income Taxes [Line Items]
U.S. Income (Loss) Before Income Taxes			$ 383,922	$ 443,991	$ (523,855)
Income Tax Expense (Benefit), Computed at U.S. Federal Statutory Rate	[1]		94,061	155,397	(183,349)
Impact of 2017 Tax Reform Act	[2]		(112,598)	0	0
State Income Taxes (Benefit)	[3]		22,203	16,641	(39,697)
Federal Tax Credits			(6,576)	(6,679)	(3,262)
Miscellaneous			(4,689)	(4,850)	(6,589)
Total Income Taxes			$ (7,599)	$ 160,509	$ (232,897)
Federal Statutory Rate			24.50%	35.00%
Estimate for potential sequestration of AMT credit refunds			$ 5,000
Income tax benefit from blended tax rate			$ 9,100
Scenario, Forecast [Member]
Income Taxes [Line Items]
Federal Statutory Rate		21.00%

[1] For fiscal 2018, represents the blended rate of 24.5%. Calculated as 35% for the first quarter of the fiscal year and 21% for the remaining three quarters.

[2] Represents the remeasurement of deferred income taxes as a result of the lower U.S. corporate income tax rate including a $5.0 million estimate for the potential sequestration of AMT credit refunds and the benefit of $9.1 million as a result of the blended tax rate described above.

[3] The state income taxes (benefit) shown above includes income tax benefits related to state enhanced oil recovery tax credits and adjustments to the estimated state effective tax rates utilized in the calculation of deferred income taxes.