Summary Of Significant Accounting Policies (Reclassification Out Of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Reclassification Adjustments out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Operating Revenues	$ 629,939	$ 717,261	$ 1,155,301	$ 1,376,119
Total Before Income Tax	221,604	190,817	397,711	418,059
Income Tax Expense	(55,332)	(49,937)	(98,419)	(107,489)
Net Income Available for Common Stock	166,272	140,880	299,292	310,570
Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustments out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Total Before Income Tax	60,148	(18,940)	79,857	(178,281)
Income Tax Expense	(16,689)	5,208	(22,158)	48,779
Net Income Available for Common Stock	43,459	(13,732)	57,699	(129,502)
Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) | Commodity Contracts | Gains and Losses on Derivative Financial Instruments
Reclassification Adjustments out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Operating Revenues	60,184	(18,768)	79,939	(177,930)
Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) | Foreign Currency Contracts | Gains and Losses on Derivative Financial Instruments
Reclassification Adjustments out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Operating Revenues	$ (36)	$ (172)	$ (82)	$ (351)