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Retirement Benefits (Summary Of Benefit Liability Recorded) (Details) - USD ($) $ in Millions | Dec. 31, 2022 | Dec. 31, 2021
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Defined Benefit Plan Disclosure [Line Items] |  |
Noncurrent asset | $ (377) | $ (717)
Union Electric Company |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Noncurrent asset | (84) | (189)
Ameren Illinois Company |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Noncurrent asset | $ (263) | $ (416)

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- Definition Amount of asset (liability), recognized in statement of financial position, for defined benefit pension and other postretirement plans. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=123453770&loc=d3e1703-114919 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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- Details
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