XML 78 R37.htm IDEA: XBRL DOCUMENT
v3.23.2

Rate And Regulatory Matters (Narrative-Illinois) (Details) $ in Millions | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2023 USD ($) | Jun. 30, 2023 USD ($) | Jun. 30, 2022 USD ($) | Jun. 30, 2023 USD ($) numberOfProposedPerformanceMetrics | Jun. 30, 2022 USD ($) | Dec. 31, 2027 USD ($) | Dec. 31, 2026 USD ($) | Dec. 31, 2025 USD ($) | Dec. 31, 2024 USD ($)
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
Revenues |  | $ 1,760 | $ 1,726 | $ 3,822 | $ 3,605 |  |  |  |
Ameren Illinois Company |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
Revenues |  | $ 779 | $ 769 | $ 1,880 | $ 1,793 |  |  |  |
Ameren Illinois Company | Minimum | Subsequent Event |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
ICC required RTO cost benefit study duration | 5 years |  |  |  |  |  |  |  |
Ameren Illinois Company | Maximum | Subsequent Event |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
ICC required RTO cost benefit study duration | 10 years |  |  |  |  |  |  |  |
Ameren Illinois Company | Electric Distribution |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
Requested Return on Equity Adjustment |  |  |  | 0.24% |  |  |  |  |
Number of Performance Metrics | numberOfProposedPerformanceMetrics |  |  |  | 7 |  |  |  |  |
IETL | Ameren Illinois Company | Electric Distribution |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
Public Utilities, Approved Equity Capital Structure, Percentage |  |  |  | 50.00% |  |  |  |  |
Amortization Period |  |  |  | 2 years |  |  |  |  |
Amortization Start Date |  |  |  | 1 year |  |  |  |  |
Multi-Year Rate Plan Reconciliation Cap |  |  |  | 105.00% |  |  |  |  |
IETL | Ameren Illinois Company | Electric Distribution | Subsequent Event |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
Multi-year rate plan requested revenue requirement |  |  |  |  |  | $ 1,560 | $ 1,484 | $ 1,387 | $ 1,291
Public Utilities, Requested Return on Equity, Percentage |  |  |  |  |  | 10.50% | 10.50% | 10.50% | 10.50%
Public Utilities, Requested Equity Capital Structure, Percentage |  |  |  |  |  | 54.03% | 54.02% | 53.97% | 53.99%
Rate Base |  |  |  |  |  | $ 5,200 | $ 4,900 | $ 4,600 | $ 4,300
Multi-year rate plan ICC staff recommended revenue requirement |  |  |  |  |  | $ 1,429 | $ 1,371 | $ 1,292 | $ 1,211
ICC recommended return on equity percentage | 5.80% |  |  |  |  | 8.90% | 8.90% | 8.90% | 8.90%
ICC staff recommended equity capital structure |  |  |  |  |  | 50.00% | 50.00% | 50.00% | 50.00%
ICC staff recommended rate base |  |  |  |  |  | $ 4,800 | $ 4,600 | $ 4,400 | $ 4,100
ICC staff estimated return on equity percentage | 8.90% |  |  |  |  |  |  |  |
Public Utilities, Requested Rate Increase (Decrease), Percentage |  |  |  |  |  |  | 50.00% |  |
Public Utilities, Requested Rate Increase (Decrease), Amount |  |  |  |  |  |  |  |  | $ 179
IETL | Ameren Illinois Company | Electric Distribution | Minimum |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
Public Utilities, Requested Rate Increase (Decrease), Percentage |  |  |  | 50.00% |  |  |  |  |
Pending Rate Case | Ameren Illinois Company |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
Electric energy-efficiency rate increase |  |  |  | $ 27 |  |  |  |  |
Pending Rate Case | Ameren Illinois Company | Electric Distribution |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
ICC staff recommended equity capital structure |  |  |  | 50.00% |  |  |  |  |
ICC staff recommended rate increase |  |  |  | $ 109 |  |  |  |  |
Pending Rate Case | Ameren Illinois Company | Electric Distribution | Subsequent Event |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
Public Utilities, Requested Equity Capital Structure, Percentage | 53.99% |  |  |  |  |  |  |  |
Public Utilities, Requested Rate Increase (Decrease), Amount | $ 125 |  |  |  |  |  |  |  |
Pending Rate Case | Ameren Illinois Company | Natural gas | Subsequent Event |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
Public Utilities, Requested Return on Equity, Percentage | 10.30% |  |  |  |  |  |  |  |
Public Utilities, Requested Equity Capital Structure, Percentage | 53.99% |  |  |  |  |  |  |  |
Rate Base | $ 2,900 |  |  |  |  |  |  |  |
ICC recommended return on equity percentage | 9.89% |  |  |  |  |  |  |  |
ICC staff recommended equity capital structure | 50.00% |  |  |  |  |  |  |  |
ICC staff recommended rate base | $ 2,900 |  |  |  |  |  |  |  |
Public Utilities, Requested Rate Increase (Decrease), Amount | 148 |  |  |  |  |  |  |  |
ICC staff recommended rate increase | 128 |  |  |  |  |  |  |  |
Revenues | $ 77 |  |  |  |  |  |  |  |
Intervenor recommended return on equity | 9.50% |  |  |  |  |  |  |  |
Intervenor recommended equity capital structure | 52.00% |  |  |  |  |  |  |  |
Pending Rate Case | Ameren Illinois Company | Natural gas | Minimum | Subsequent Event |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
Intervenor recommended rate increase | $ 98 |  |  |  |  |  |  |  |
Pending Rate Case | Ameren Illinois Company | Natural gas | Maximum | Subsequent Event |  |  |  |  |  |  |  |  |
Rate And Regulatory Matters [Line Items] |  |  |  |  |  |  |  |  |
Intervenor recommended rate increase | $ 106 |  |  |  |  |  |  |  |

X
- Definition Amortization period of a regulatory asset or liability + References No definition available. + Details
Name: | aee_AmortizationPeriod
Namespace Prefix: | aee_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The date amortization of a regulatory asset or liability begins. + References No definition available. + Details
Name: | aee_AmortizationStartDate
Namespace Prefix: | aee_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Electric energy-efficiency rate increase + References No definition available. + Details
Name: | aee_ElectricEnergyEfficiencyRateIncrease
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition ICC required RTO cost benefit study duration + References No definition available. + Details
Name: | aee_ICCRequiredRTOCostBenefitStudyDuration
Namespace Prefix: | aee_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The return on equity percentage estimated by the ICC staff. + References No definition available. + Details
Name: | aee_ICCStaffEstimatedReturnOnEquityPercentage
Namespace Prefix: | aee_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The equity capital percentage recommend by the ICC staff. + References No definition available. + Details
Name: | aee_ICCStaffRecommendedEquityCapitalStructure
Namespace Prefix: | aee_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The rate base recommended by the ICC staff. + References No definition available. + Details
Name: | aee_ICCStaffRecommendedRateBase
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The rate increase recommended by the ICC staff. + References No definition available. + Details
Name: | aee_ICCStaffRecommendedRateIncrease
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The return on equity percentage recommended by the ICC staff. + References No definition available. + Details
Name: | aee_ICCStaffRecommendedReturnOnEquityPercentage
Namespace Prefix: | aee_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The equity capital structure recommended by intervenors. + References No definition available. + Details
Name: | aee_IntervenorRecommendedEquityCapitalStructure
Namespace Prefix: | aee_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The rate increase recommended by intervenors. + References No definition available. + Details
Name: | aee_IntervenorRecommendedRateIncrease
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The return on equity recommended by intervenors. + References No definition available. + Details
Name: | aee_IntervenorRecommendedReturnOnEquity
Namespace Prefix: | aee_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The revenue requirement recommended by the ICC staff. + References No definition available. + Details
Name: | aee_MultiYearRatePlanICCStaffRecommendedRevenueRequirement
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Multi-Year Rate Plan Reconciliation Cap + References No definition available. + Details
Name: | aee_MultiYearRatePlanReconciliationCap
Namespace Prefix: | aee_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Ameren Illinois' requested multi-year rate plan revenue requirement. + References No definition available. + Details
Name: | aee_MultiYearRatePlanRequestedRevenueRequirement
Namespace Prefix: | aee_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Number of Performance Metrics + References No definition available. + Details
Name: | aee_NumberOfPerformanceMetrics
Namespace Prefix: | aee_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Rate And Regulatory Matters [Line Items] + References No definition available. + Details
Name: | aee_RateAndRegulatoryMattersLineItems
Namespace Prefix: | aee_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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 The return on equity adjustments related to the achievement of certain performance metrics requested by Ameren Illinois. + References No definition available. + Details
Name: | aee_RequestedReturnOnEquityAdjustment
Namespace Prefix: | aee_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
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 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
- Definition Percentage of public utility's requested rate increase (decrease) with regulatory agency. + References No definition available. + Details
Name: | us-gaap_PublicUtilitiesRequestedRateIncreaseDecreasePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(g)(1)(ii)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 28 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482907/825-10-50-28 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 220 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(1)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(4)(i)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(4)(ii)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(4)(iii)(A)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(4)(iv)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1A -Subparagraph (SX 210.13-01(a)(5)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(4)(i)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(4)(iii)(A)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(4)(iii)(B)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(4)(iv)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Topic 470 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1B -Subparagraph (SX 210.13-02(a)(5)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 30 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-30 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 42 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-42 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 22 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-22 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 32 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-32 Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 40 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-40 Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 22 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-22 Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 32 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-32 Reference 22: http://www.xbrl.org/2003/role/disclosureRef -Topic 280 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 41 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482810/280-10-50-41 Reference 23: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 235 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-05(b)(2)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479557/942-235-S99-1 + Details
Name: | us-gaap_Revenues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=aee_AmerenIllinoisCompanyMember
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_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
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: | us-gaap_PublicUtilityAxis=us-gaap_ElectricDistributionMember
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_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: |