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v3.23.3

Summary of Significant Accounting Policies - General (Details) $ in Millions | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | ---
Sep. 30, 2023 USD ($) People | Sep. 30, 2022 USD ($) | Sep. 30, 2021 USD ($) | Sep. 30, 2020 USD ($) | Sep. 30, 2016 USD ($)
Accounting Policies [Abstract] |  |  |  |  |
Cash and Cash Equivalents, at Carrying Value | $ 501 | $ 500 |  |  |
Reimbursements from DOE | 219 |  |  |  |
Restricted Cash and Investments, Noncurrent | 20 | 20 |  |  |
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents | 521 | 520 | $ 518 | $ 521 |
Accounts receivable from DOE | 11 |  |  |  |
Appropriation-investment power program | $ 258 | 258 |  |  | $ 1,000
Population of Service Area [Line Items] |  |  |  |  |
Population of service area | People | 10,000,000 |  |  |  |
Cash and Cash Equivalents, at Carrying Value | $ 501 | 500 |  |  |
Restricted Cash and Investments, Noncurrent | $ 20 | $ 20 |  |  |

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- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(1)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483467/210-10-45-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-4 + Details
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