XML 69 R36.htm IDEA: XBRL DOCUMENT
v3.25.3

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions | Sep. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Basis Of Presentation And Significant Accounting Policies [Line Items] |  |
Unconsolidated variable interest | $ 60 | $ 74
Cash Surrender Value of Life Insurance | 220 | 260
Corporate owned life insurance, borrowings | 117 | 110
Ameren Illinois Company |  |
Basis Of Presentation And Significant Accounting Policies [Line Items] |  |
Cash Surrender Value of Life Insurance | 124 | 118
Corporate owned life insurance, borrowings | 117 | $ 110
Partnership Funding Commitment |  |
Basis Of Presentation And Significant Accounting Policies [Line Items] |  |
Outstanding funding commitments | $ 31 |

X
- Definition Basis Of Presentation And Significant Accounting Policies [Line Items] + References No definition available. + Details
Name: | aee_BasisOfPresentationAndSignificantAccountingPoliciesLineItems
Namespace Prefix: | aee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Corporate Owned Life Insurance, Borrowings + References No definition available. + Details
Name: | aee_CorporateOwnedLifeInsuranceBorrowings
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(17)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_CashSurrenderValueOfLifeInsurance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Portion of equity (net assets) in a variable interest entity (VIE) not attributable, directly or indirectly, to the parent entity. That is, this is the portion of equity in a VIE that is attributable to the noncontrolling interest (previously referred to as minority interest). + References No definition available. + Details
Name: | us-gaap_NoncontrollingInterestInVariableInterestEntity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of unrecorded obligation to transfer funds in future for fixed or minimum amount or quantity of product and service at fixed or minimum price. Includes, but is not limited to, lease not yet commenced and take-or-pay and throughput contracts. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 440 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482648/440-10-50-4 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478964/842-20-50-3 + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceSheetAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Details
Name: | us-gaap_LongTermPurchaseCommitmentByCategoryOfItemPurchasedAxis=aee_PartnershipFundingCommitmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |