Consolidated Statements Of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net Income Available for Common Stock	$ 166,272	$ 140,880	$ 299,292	$ 310,570
Other Comprehensive Income (Loss), Before Tax:
Unrealized Gain (Loss) on Derivative Financial Instruments Arising During the Period	71,164	310,544	260,331	608,137
Reclassification Adjustment for Realized (Gains) Losses on Derivative Financial Instruments in Net Income	(60,148)	18,940	(79,857)	178,281
Other Comprehensive Income (Loss), Before Tax	11,016	329,484	180,474	786,418
Income Tax Expense (Benefit) Related to Unrealized Gain (Loss) on Derivative Financial Instruments Arising During the Period	19,746	85,394	72,232	166,770
Reclassification Adjustment for Income Tax Benefit (Expense) on Realized Losses (Gains) from Derivative Financial Instruments in Net Income	(16,689)	5,208	(22,158)	48,779
Income Taxes – Net	3,057	90,602	50,074	215,549
Other Comprehensive Income (Loss)	7,959	238,882	130,400	570,869
Comprehensive Income	$ 174,231	$ 379,762	$ 429,692	$ 881,439