XML 152 R79.htm IDEA: XBRL DOCUMENT
v3.25.4

Callaway Energy Center (Narrative) (Details) - Ameren Missouri - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2025 | Dec. 31, 2025
Nuclear Waste Matters [Line Items] |  |
Decommissioning Cost |  | $ 7
Frequency of Decommissioning Cost Study |  | 3 years
Future Decommissioning Cost | $ 0 |
Minimum | Nuclear Decommissioning Trust Fund |  |
Nuclear Waste Matters [Line Items] |  |
Trust Fund Investments, Target Allocation Percentage |  | 60.00%
Maximum | Nuclear Decommissioning Trust Fund |  |
Nuclear Waste Matters [Line Items] |  |
Trust Fund Investments, Target Allocation Percentage |  | 70.00%

X
- Definition Annual Decommissioning Cost + References No definition available. + Details
Name: | aee_DecommissioningCost
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Frequency of Decommissioning Cost Study + References No definition available. + Details
Name: | aee_FrequencyOfDecommissioningCostStudy
Namespace Prefix: | aee_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Future Decommissioning Cost + References No definition available. + Details
Name: | aee_FutureDecommissioningCost
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition [Line Items] for Nuclear Waste Matters [Table] + References No definition available. + Details
Name: | aee_NuclearWasteMattersLineItems
Namespace Prefix: | aee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Trust Fund Investments, Target Allocation Percentage + References No definition available. + Details
Name: | aee_TrustFundInvestmentsTargetAllocationPercentage
Namespace Prefix: | aee_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

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

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RegulatoryAssetAxis=aee_NuclearDecommissioningTrustFundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |