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Risk Management Activities and Derivative Transactions Counterparty Credit Risk (Details) $ in Millions | 9 Months Ended |
--- | --- | ---
Jun. 30, 2024 USD ($) Customers | Jun. 30, 2023 | Sep. 30, 2023 USD ($)
Derivative |  |  |
Accounts Receivable, before Allowance for Credit Loss, Current | $ | $ 1,574 |  | $ 1,627
Two Largest Customer Percentage of Total Operating Revenue | 1600.00% | 1600.00% |
Moody's, A1 Rating [Member] |  |  |
Derivative |  |  |
Natural Gas Banking Counterparties Credit Rating | A1 |  |
Moody's, B1 Rating [Member] |  |  |
Derivative |  |  |
Natural Gas Banking Counterparties Credit Rating | B1 |  |
Moody's, A2 Rating |  |  |
Derivative |  |  |
Banking Counterparties Credit Rating | A2 |  |
Credit of Customers |  |  |
Derivative |  |  |
Number of customers that represent the percent of sales | 2 |  |
Number of customers that represent the percent of sales | 2 |  |

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