XML 92 R53.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Commitments And Contingencies (Environmental Matters) (Detail) $ in Millions | 9 Months Ended |
--- | --- | ---
Sep. 30, 2022 USD ($) energyCenter scrubber site | Dec. 31, 2021 USD ($)
Loss Contingencies [Line Items] |  |
Asset Retirement Obligation | $ 778 | $ 764
Minimum |  |
Loss Contingencies [Line Items] |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | 125 |
Maximum |  |
Loss Contingencies [Line Items] |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | $ 175 |
Union Electric Company |  |
Loss Contingencies [Line Items] |  |
Number of Energy Center Scrubbers | scrubber | 2 |
Number of Energy Centers Constructing Wastewater Treatment Facilities | energyCenter | 3 |
Number of energy centers | energyCenter | 4 |
Number of Days to Comply after Final EPA Determination | 135 days |
Asset Retirement Obligation | $ 774 | 760
Number of Ameren Missouri Natural Gas Energy Centers Subject To IETL | energyCenter | 4 |
Union Electric Company | Coal Fired Electric Generation Equipment |  |
Loss Contingencies [Line Items] |  |
Plant To Be Abandoned, Net | $ 600 |
Union Electric Company | Minimum |  |
Loss Contingencies [Line Items] |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | 125 |
Union Electric Company | Maximum |  |
Loss Contingencies [Line Items] |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | 175 |
Ameren Illinois Company |  |
Loss Contingencies [Line Items] |  |
Asset Retirement Obligation | 4 | $ 4
Coal Combustion Residuals Estimate | Union Electric Company | Minimum |  |
Loss Contingencies [Line Items] |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | 60 |
Coal Combustion Residuals Estimate | Union Electric Company | Maximum |  |
Loss Contingencies [Line Items] |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | 80 |
Manufactured Gas Plant |  |
Loss Contingencies [Line Items] |  |
Accrual for environmental loss contingencies | $ 71 |
Manufactured Gas Plant | Ameren Illinois Company |  |
Loss Contingencies [Line Items] |  |
Number of remediation sites | site | 44 |
Accrual for environmental loss contingencies | $ 71 |
Manufactured Gas Plant | Ameren Illinois Company | Minimum |  |
Loss Contingencies [Line Items] |  |
Estimate of possible loss | 71 |
Manufactured Gas Plant | Ameren Illinois Company | Maximum |  |
Loss Contingencies [Line Items] |  |
Estimate of possible loss | 145 |
Rush Island Energy Center | Union Electric Company |  |
Loss Contingencies [Line Items] |  |
Rate Base | 500 |
New CCR Rules Estimate |  |
Loss Contingencies [Line Items] |  |
Asset Retirement Obligation | 49 |
New CCR Rules Estimate | Union Electric Company |  |
Loss Contingencies [Line Items] |  |
Asset Retirement Obligation | $ 49 |

X
- Definition Estimated capital costs to comply with existing and known federal and state air emission standards. + References No definition available. + Details
Name: | aee_Estimatedcapitalcoststocomplywithexistingandknownfederalandstateairemissionstandards.
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of Ameren Missouri Natural Gas Energy Centers Subject To IETL emission standards. + References No definition available. + Details
Name: | aee_NumberOfAmerenMissouriNaturalGasEnergyCentersSubjectToIETL
Namespace Prefix: | aee_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of Days to Comply after Final EPA Determination + References No definition available. + Details
Name: | aee_NumberOfDaysToComplyAfterFinalEPADetermination
Namespace Prefix: | aee_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Energy Center Scrubbers to achieve compliance with regulations + References No definition available. + Details
Name: | aee_NumberOfEnergyCenterScrubbers
Namespace Prefix: | aee_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of Energy Centers + References No definition available. + Details
Name: | aee_NumberOfEnergyCenters
Namespace Prefix: | aee_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number Of Energy Centers Constructing Wastewater Treatment Facilities + References No definition available. + Details
Name: | aee_NumberOfEnergyCentersConstructingWastewaterTreatmentFacilities
Namespace Prefix: | aee_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number Of Remediation Sites + References No definition available. + Details
Name: | aee_NumberOfRemediationSites
Namespace Prefix: | aee_
Data Type: | xbrli:positiveIntegerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Plant To Be Abandoned, Net + References No definition available. + Details
Name: | aee_PlantToBeAbandonedNet
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Value established for a utility on which the entity is allowed to earn a particular rate of return + References No definition available. + Details
Name: | aee_RateBase
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Total costs accrued as of the balance sheet date for environmental loss contingencies. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 25 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859 + Details
Name: | us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition Reflects the estimated amount of loss from the specified contingency as of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14435-108349 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14557-108349 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=124440162&loc=d3e12021-110248 + Details
Name: | us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
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: |

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

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=aee_CoalFiredElectricGenerationEquipmentMember
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_LossContingenciesByNatureOfContingencyAxis=aee_CoalCombustionResidualsEstimateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=aee_ManufacturedGasPlantMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=aee_RushIslandEnergyCenterMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=aee_NewCCRRulesEstimateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |