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Supplemental Information (Schedule of Asset Retirement Obligations (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] |  |  |
Asset Retirement Obligation | $ 827 | $ 791 | $ 786
Liabilities incurred | 21 | 0 |
Liabilities settled | (13) | (10) |
Accretion | 35 | 33 |
Change in estimates | (7) | (18) |
Current asset retirement obligations | 5 | 19 |
Nuclear Plant |  |  |
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] |  |  |
Asset Retirement Obligation | 648 |  |
Ameren Missouri |  |  |
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] |  |  |
Asset Retirement Obligation | 823 | 787 | 782
Liabilities incurred | 21 | 0 |
Liabilities settled | (13) | (10) |
Accretion | 35 | 33 |
Change in estimates | (7) | (18) |
Ameren Illinois |  |  |
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] |  |  |
Asset Retirement Obligation | 4 | 4 | $ 4
Liabilities incurred | 0 | 0 |
Liabilities settled | 0 | 0 |
Accretion | 0 | 0 |
Change in estimates | $ 0 | $ 0 |

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- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 25 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481999/410-20-25-4 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
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- Definition Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481879/410-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
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- Definition Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
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- Definition Amount of asset retirement obligations incurred during the period. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
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- Definition Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 410 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481850/410-20-50-1 + Details
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