XML 167 R87.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Retirement Benefits (Fair Value Of Plan Assets Utilizing Fair Value Hierarchy) (Details) - USD ($) $ in Millions | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
--- | --- | --- | ---
Pension Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | $ 4,272 | $ 4,027 | $ 5,745
Pension Benefits | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 718 | 584 |
Pension Benefits | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 1,529 | 1,304 |
Pension Benefits | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 2,256 | 2,271 |
Pension Benefits | Includes Medical Benefit Component Under Section401 H And Excludes Receivables Related To Pending Security Sales [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 4,503 | 4,159 |
Pension Benefits | Cash and cash equivalents |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 90 | 172 |
Pension Benefits | Cash and cash equivalents | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Cash and cash equivalents | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Cash and cash equivalents | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 90 | 172 |
Pension Benefits | U.S. large-capitalization |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 663 | 658 |
Pension Benefits | U.S. large-capitalization | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | U.S. large-capitalization | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | U.S. large-capitalization | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 663 | 658 |
Pension Benefits | U.S. small- and mid-capitalization |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 353 | 321 |
Pension Benefits | U.S. small- and mid-capitalization | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 353 | 321 |
Pension Benefits | U.S. small- and mid-capitalization | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | U.S. small- and mid-capitalization | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | International |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 545 | 661 |
Pension Benefits | International | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 316 | 266 |
Pension Benefits | International | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | International | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 229 | 395 |
Pension Benefits | Global |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 721 | 493 |
Pension Benefits | Global | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Global | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Global | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 721 | 493 |
Pension Benefits | Corporate bonds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 479 | 397 |
Pension Benefits | Corporate bonds | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Corporate bonds | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 479 | 397 |
Pension Benefits | Corporate bonds | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Municipal bonds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 43 | 41 |
Pension Benefits | Municipal bonds | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Municipal bonds | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 43 | 41 |
Pension Benefits | Municipal bonds | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | U.S. Treasury and agency securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 994 | 859 |
Pension Benefits | U.S. Treasury and agency securities | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | U.S. Treasury and agency securities | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 994 | 859 |
Pension Benefits | U.S. Treasury and agency securities | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Diversified Credit |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 305 |  |
Pension Benefits | Diversified Credit | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Diversified Credit | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Diversified Credit | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 305 | 281 |
Pension Benefits | Other |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 62 | 4 |
Pension Benefits | Other | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 49 | (3) |
Pension Benefits | Other | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 13 | 7 |
Pension Benefits | Other | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Real estate |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 248 | 271 |
Pension Benefits | Real estate | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Real estate | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Real estate | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 248 | 271 |
Pension Benefits | Private equity |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 1 |
Pension Benefits | Private equity | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Private equity | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Pension Benefits | Private equity | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 1 |
Pension Benefits | Medical benefit assets |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | (196) | (172) |
Pension Benefits | Net receivables |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | (35) | 40 |
Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 1,393 | 1,249 | $ 1,558
Postretirement Benefits | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 459 | 370 |
Postretirement Benefits | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 161 | 123 |
Postretirement Benefits | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 575 | 582 |
Postretirement Benefits | Includes Medical Benefit Component Under Section401 H And Excludes Receivables Related To Pending Security Sales [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 1,195 | 1,075 |
Postretirement Benefits | Cash and cash equivalents |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 10 | 14 |
Postretirement Benefits | Cash and cash equivalents | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 10 | 14 |
Postretirement Benefits | Cash and cash equivalents | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | Cash and cash equivalents | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | U.S. large-capitalization |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 383 | 308 |
Postretirement Benefits | U.S. large-capitalization | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 302 | 221 |
Postretirement Benefits | U.S. large-capitalization | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | U.S. large-capitalization | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 81 | 87 |
Postretirement Benefits | U.S. small- and mid-capitalization |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 96 | 92 |
Postretirement Benefits | U.S. small- and mid-capitalization | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 96 | 92 |
Postretirement Benefits | U.S. small- and mid-capitalization | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | U.S. small- and mid-capitalization | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | International |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 100 | 141 |
Postretirement Benefits | International | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 51 | 43 |
Postretirement Benefits | International | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | International | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 49 | 98 |
Postretirement Benefits | Global |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 174 | 110 |
Postretirement Benefits | Global | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | Global | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | Global | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 174 | 110 |
Postretirement Benefits | Municipal bonds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 161 | 123 |
Postretirement Benefits | Municipal bonds | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | Municipal bonds | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 161 | 123 |
Postretirement Benefits | Municipal bonds | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | Other |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 271 | 287 |
Postretirement Benefits | Other | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | Other | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 0 | 0 |
Postretirement Benefits | Other | NAV |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 271 | 287 |
Postretirement Benefits | Medical benefit assets |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | 196 | 172 |
Postretirement Benefits | Net receivables |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets | $ 2 | $ 2 |

X
- 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
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(02) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 6: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(ii) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 Reference 7: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(iv)(01) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
Name: | us-gaap_DefinedBenefitPlanFairValueOfPlanAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=aee_IncludesMedicalBenefitComponentUnderSection401HAndExcludesReceivablesRelatedToPendingSecuritySalesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CashAndCashEquivalentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanEquitySecuritiesUsLargeCapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=aee_USSmallAndMidCapitalizationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=aee_GlobalMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_MunicipalBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=aee_DiversifiedCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_RealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_PrivateEquityFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=aee_MedicalBenefitComponentExcludedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=aee_PendingSecuritySalesIncludedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |