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v3.25.1

Debt and Other Obligations Debt Securities Activity (Details) - USD ($) $ in Millions | 6 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Oct. 02, 2024 | Sep. 30, 2024
Debt Instrument |  |  |  |  |  |
Total long-term debt, net |  | $ 19,385 |  |  |  | $ 18,764
Repayments of Unsecured Debt |  | 1 | [1] | $ 1 |  |
Amount of letters of credit outstanding |  | $ 6 |  |  |  |
Percent of par value | [1] | 100.00% |  |  |  |
Long-term power bonds, net |  | $ 17,729 |  |  |  | $ 17,867
Repayments of Other Long-term Debt |  | $ 18 |  | $ 17 |  |
Debt Instrument, Redemption, Description |  | 19 |  |  |  |
Proceeds from Issuance of Debt |  | $ 2,031 |  |  |  |
Debt Instrument, Unamortized Discount (Premium), Net |  | $ 19 |  |  |  |
880591FC1 |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |
Percent of par value |  | 98.517% |  |  |  |
Long-term power bonds, net |  | $ 1,250 |  |  |  |
Variable Interest Entity, Primary Beneficiary [Member] |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |
Debt and Lease Obligation |  |  |  |  | $ 800 |
2009 series B |  |  |  |  |  |
Debt Instrument |  |  |  |  |  |
Repayments of Unsecured Debt |  | $ 1 |  |  |  |
[1] | (2) All redemptions were at 100 percent of par.

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