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v3.25.3

Subsequent Events (Details) - USD ($) $ in Millions | Sep. 30, 2025 | Oct. 02, 2024 | Sep. 30, 2024 | Sep. 30, 2013 | Sep. 30, 2012
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Debt Instrument, Redemption [Line Items] |  |  |  |  |
Non-current regulatory liabilities | $ 141 |  | $ 83 |  |
Regulatory assets | 8,047 |  | 9,408 |  |
Face Amount | 40 |  |  | $ 360 |
Long-term debt of variable interest entities, net | 1,632 |  | 897 |  |
Current maturities of long-term debt of variable interest entities issued at par | 49 |  | 37 |  |
JACTG |  |  |  |  |
Debt Instrument, Redemption [Line Items] |  |  |  |  |
Face Amount |  | $ 720 |  |  |
Variable Interest Entity, Primary Beneficiary [Member] |  |  |  |  |
Debt Instrument, Redemption [Line Items] |  |  |  |  |
Debt and Lease Obligation |  | $ 800 | 0 |  |
Holdco |  |  |  |  |
Debt Instrument, Redemption [Line Items] |  |  |  |  |
Face Amount |  |  |  |  | $ 100
Unrealized gains/losses on commodity derivatives |  |  |  |  |
Debt Instrument, Redemption [Line Items] |  |  |  |  |
Regulatory assets | 12 |  | 64 |  |
Unrealized gains/losses on commodity derivatives |  |  |  |  |
Debt Instrument, Redemption [Line Items] |  |  |  |  |
Non-current regulatory liabilities | $ 10 |  | $ 2 |  |

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