XML 130 R57.htm IDEA: XBRL DOCUMENT
v3.25.4

Rate And Regulatory Matters (Narrative-Illinois) (Details) $ in Millions | 1 Months Ended | 12 Months Ended
--- | --- | ---
Jan. 31, 2026 USD ($) | Nov. 30, 2025 USD ($) | Oct. 31, 2023 USD ($) | Dec. 31, 2029 USD ($) | Dec. 31, 2028 USD ($) | Dec. 31, 2027 USD ($) | Dec. 31, 2026 USD ($) | Dec. 31, 2025 USD ($) | Dec. 31, 2024 USD ($) | Dec. 31, 2023 USD ($)
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Capital expenditures |  |  |  |  |  |  |  | $ 4,128 | $ 4,319 | $ 3,597
Forecast |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Capital expenditures |  |  |  |  |  |  | $ 1,300 |  |  |
Ameren Illinois |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Annual investment in energy-efficiency programs |  |  |  |  |  |  |  | $ 126 |  |
Basis points for ROE modification |  |  |  |  |  |  |  | 0.0200 |  |
Capital expenditures |  |  |  |  |  |  |  | $ 1,481 | $ 1,467 | $ 1,731
Ameren Illinois | Forecast |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Annual investment in energy-efficiency programs |  |  |  | $ 256 | $ 222 | $ 178 |  |  |  |
IETL | Electric Distribution | Ameren Illinois |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Multi-year rate plan approved revenue requirement |  |  |  |  |  |  |  | 1,206 |  |
Approved rate increase (decrease), amount |  |  |  |  |  |  |  | 308 |  |
IETL | Electric Distribution | Ameren Illinois | Forecast |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Multi-year rate plan approved revenue requirement |  |  |  |  | $ 1,421 | $ 1,367 | $ 1,287 |  |  |
Pending Rate Case | Electric Distribution | Ameren Illinois |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Cumulative rate increase |  |  |  |  |  |  |  | 48 |  |
Approved rate base |  |  |  |  |  |  |  | $ 4,200 |  |
Percentage of requested equity capital structure |  |  |  |  |  |  |  | 50.00% |  |
Pending Rate Case | Natural gas | Ameren Illinois |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Capital expenditures |  | $ 75 | $ 30 |  |  |  |  |  |  |
Eligible QIP investments |  |  | $ 529 |  |  |  |  |  |  |
Pending Rate Case | Electric Energy-Efficiency | Ameren Illinois |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Cumulative rate increase |  | 138 |  |  |  |  |  |  |  |
Approved rate base |  | 474 |  |  |  |  |  |  |  |
Pending Rate Case | Electric Energy-Efficiency | Ameren Illinois | Subsequent Event |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Cumulative rate increase | $ 12 |  |  |  |  |  |  |  |  |
Final Rate Order | Natural gas | Ameren Illinois |  |  |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |  |  |
Cumulative rate increase |  | 79 |  |  |  |  |  |  |  |
Approved rate base |  | $ 3,200 |  |  |  |  |  |  |  |
Public Utilities, Approved Return on Equity, Percentage |  | 9.60% |  |  |  |  |  |  |  |
Public Utilities, Approved Equity Capital Structure, Percentage |  | 50.00% |  |  |  |  |  |  |  |
Capital expenditures |  | $ 75 |  |  |  |  |  |  |  |

X
- Definition Annual investment in energy-efficiency programs. + References No definition available. + Details
Name: | aee_AnnualInvestmentInEnergyEfficiencyPrograms
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Approved rate base + References No definition available. + Details
Name: | aee_ApprovedRateBase
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Basis points for ROE modification + References No definition available. + Details
Name: | aee_BasisPointsForROEModification
Namespace Prefix: | aee_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Eligible QIP investments + References No definition available. + Details
Name: | aee_EligibleQIPInvestments
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Multi-year rate plan revenue requirement approved by the ICC. + References No definition available. + Details
Name: | aee_MultiYearRatePlanApprovedRevenueRequirement
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 13 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-13 + Details
Name: | us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of public utility's approved equity to capital, including debt and equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesApprovedEquityCapitalStructurePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of public utility's approved rate increase (decrease) by regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesApprovedRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of public utility's approved return on equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesApprovedReturnOnEquityPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
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_PublicUtilitiesGeneralDisclosuresLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of public utility's requested equity to capital, including debt and equity. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedEquityCapitalStructurePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of public utility's requested rate increase (decrease) with regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedRateIncreaseDecreaseAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | srt_StatementScenarioAxis=srt_ScenarioForecastMember
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_PublicUtilitiesRegulatoryProceedingAxis=aee_IETLMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=us-gaap_ElectricDistributionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilitiesRegulatoryProceedingAxis=aee_PendingRateCaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=srt_NaturalGasReservesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=aee_ElectricEnergyEfficiencyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilitiesRegulatoryProceedingAxis=aee_FinalRateOrderMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |