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Summary Of Significant Accounting Policies (Components 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
Accumulated Other Comprehensive Income (Loss) [Roll Forward] |  |  |  |
Beginning balance | $ 67,381 | $ (293,746) | $ (55,060) | $ (625,733)
Other Comprehensive Gains and Losses Before Reclassifications | 51,418 | 225,150 | 188,099 | 441,367
Amounts Reclassified From Other Comprehensive Income | (43,459) | 13,732 | (57,699) | 129,502
Ending balance | 75,340 | (54,864) | 75,340 | (54,864)
Gains and Losses on Derivative Financial Instruments |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Roll Forward] |  |  |  |
Beginning balance | 127,064 | (240,176) | 4,623 | (572,163)
Other Comprehensive Gains and Losses Before Reclassifications | 51,418 | 225,150 | 188,099 | 441,367
Amounts Reclassified From Other Comprehensive Income | (43,459) | 13,732 | (57,699) | 129,502
Ending balance | 135,023 | (1,294) | 135,023 | (1,294)
Funded Status of the Pension and Other Post-Retirement Benefit Plans |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Roll Forward] |  |  |  |
Beginning balance | (59,683) | (53,570) | (59,683) | (53,570)
Other Comprehensive Gains and Losses Before Reclassifications | 0 | 0 | 0 | 0
Amounts Reclassified From Other Comprehensive Income | 0 | 0 | 0 | 0
Ending balance | $ (59,683) | $ (53,570) | $ (59,683) | $ (53,570)

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