XML 85 R53.htm IDEA: XBRL DOCUMENT
v3.23.1

Related Party Transactions (Effects of Related-party Transactions on the Statement of Income) (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2023 | Mar. 31, 2022
Union Electric Company | Ameren Missouri Power Supply Agreements with Ameren Illinois |  |
Related Party Transaction [Line Items] |  |
Operating Revenues | $ 1 | $ 4
Union Electric Company | Ameren Missouri and Ameren Illinois Rent and Facility Services |  |
Related Party Transaction [Line Items] |  |
Operating Revenues | 10 | 6
Operating Expenses | 1 | 1
Union Electric Company | Ameren Missouri and Ameren Illinois Miscellaneous Support Services |  |
Related Party Transaction [Line Items] |  |
Operating Revenues | 1 | 1
Union Electric Company | Total Related Party Operating Revenues |  |
Related Party Transaction [Line Items] |  |
Operating Revenues | 10 | 10
Union Electric Company | Ameren Missouri and Ameren Illinois Transmission Services from ATXI |  |
Related Party Transaction [Line Items] |  |
Operating Expenses | 1 | 1
Union Electric Company | Purchased Power |  |
Related Party Transaction [Line Items] |  |
Operating Expenses | 1 | 1
Union Electric Company | Ameren Services Support Services Agreement |  |
Related Party Transaction [Line Items] |  |
Operating Expenses | 35 | 38
Union Electric Company | Total Related Party Other Operations and Maintenance |  |
Related Party Transaction [Line Items] |  |
Operating Expenses | 35 | 38
Union Electric Company | Money pool borrowings (advances) |  |
Related Party Transaction [Line Items] |  |
Interest Charges (Income) | 1 | 1
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Rent and Facility Services |  |
Related Party Transaction [Line Items] |  |
Operating Revenues | 1 | 1
Operating Expenses | 2 | 1
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Miscellaneous Support Services |  |
Related Party Transaction [Line Items] |  |
Operating Revenues | 1 | 1
Ameren Illinois Company | Total Related Party Operating Revenues |  |
Related Party Transaction [Line Items] |  |
Operating Revenues | 1 | 1
Ameren Illinois Company | Ameren Illinois Power Supply Agreements with Ameren Missouri |  |
Related Party Transaction [Line Items] |  |
Operating Expenses | 1 | 4
Ameren Illinois Company | Ameren Missouri and Ameren Illinois Transmission Services from ATXI |  |
Related Party Transaction [Line Items] |  |
Operating Expenses | 1 | 1
Ameren Illinois Company | Purchased Power |  |
Related Party Transaction [Line Items] |  |
Operating Expenses | 1 | 4
Ameren Illinois Company | Ameren Services Support Services Agreement |  |
Related Party Transaction [Line Items] |  |
Operating Expenses | 35 | 35
Ameren Illinois Company | Total Related Party Other Operations and Maintenance |  |
Related Party Transaction [Line Items] |  |
Operating Expenses | 37 | 36
Ameren Illinois Company | Money pool borrowings (advances) |  |
Related Party Transaction [Line Items] |  |
Interest Charges (Income) | $ 1 | $ 1

X
- Definition Amount of interest expense incurred on a debt or other obligation to related party. + References No definition available. + Details
Name: | us-gaap_InterestExpenseRelatedParty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 + Details
Name: | us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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_RelatedPartyTransactionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(4)(iv)) -URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-07.1(c)) -URI http://asc.fasb.org/extlink&oid=120401555&loc=SL114874292-224272 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(4)(iii)(B)) -URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(4)(iii)(C)) -URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(5)) -URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(5)) -URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(4)(iv)) -URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756 Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(e)) -URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227 + Details
Name: | us-gaap_RevenueFromRelatedParties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=aee_UnionElectricCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=aee_AmerenMissouriPowerSupplyAgreementsWithAmerenIllinoisMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=aee_AmerenMissouriAndAmerenIllinoisRentAndFacilityServicesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=aee_AmerenMissouriandAmerenIllinoismiscellaneoussupportservicesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=aee_TotalRelatedPartyOperatingRevenuesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=aee_AmerenMissouriAndAmerenIllinoisTransmissionServicesFromATXIMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=aee_PurchasedPowerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=aee_AmerenServicesSupportServicesAgreementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=aee_TotalRelatedPartyOtherOperationsandMaintenanceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=aee_MoneyPoolMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=aee_AmerenIllinoisCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=aee_AmerenIllinoisPowerSupplyAgreementsWithAmerenMissouriMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |