Amortization period of a regulatory asset or liability

No definition available.

Name:	aee_AmortizationPeriod
Namespace Prefix:	aee_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- 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

- 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

- Definition

Revenue requirement for the electric energy-efficiency investment

+ References

No definition available.

+ Details

Name:	aee_ElectricEnergyEfficiencyRevenueRequirement
Namespace Prefix:	aee_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amounts collected from customers to fund the Energy Transition Assistance Fund.

+ References

No definition available.

+ Details

Name:	aee_EnergyTransitionAssistanceFundSurcharge
Namespace Prefix:	aee_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The length of time the ICC required RTO cost benefit study will cover.

+ References

No definition available.

+ Details

Name:	aee_ICCRequiredRTOCostBenefitStudyDuration
Namespace Prefix:	aee_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Multi-Year Rate Plan Reconciliation Cap

+ References

No definition available.

+ Details

Name:	aee_MultiYearRatePlanReconciliationCap
Namespace Prefix:	aee_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- 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

- 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

- Definition

The number or solar generation pilot projects allowed under the CEJA.

+ References

No definition available.

+ Details

Name:	aee_NumberOfSolarGenerationPilotProjects
Namespace Prefix:	aee_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- 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

- Definition

How often a rate case may be filed.

+ References

No definition available.

+ Details

Name:	aee_RateCaseFilingFrequency
Namespace Prefix:	aee_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- 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-types:percentItemType
Balance Type:	na
Period Type:	duration

- 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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

- 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

- 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

- 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

- 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

- 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

- 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

- 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=123596393&loc=d3e14064-108612

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9031-108599

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9038-108599

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9054-108599

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 20: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 235
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-URI http://asc.fasb.org/extlink&oid=120399901&loc=d3e537907-122884

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442552-122756

Reference 22: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-URI http://asc.fasb.org/extlink&oid=124359900&loc=SL124442526-122756

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(1))
-URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227

+ Details

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=aee_AmerenIllinoisCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=aee_IETLMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_PublicUtilityAxis=us-gaap_ElectricityGenerationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=aee_IEIMAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_PublicUtilitiesRegulatoryProceedingAxis=aee_RenewableEnergyCreditsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_RegulatoryAssetAxis=aee_IEIMAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RegulatoryAssetAxis=aee_FEJAenergyefficiencyriderDomain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Rate And Regulatory Matters (Narrative-Illinois) (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2023 USD ($)	Dec. 31, 2027 USD ($)	Dec. 31, 2026 USD ($)	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2022 USD ($) numberOfProposedPerformanceMetrics windGenerationFacility	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Public Utilities, General Disclosures [Line Items]
Revenues						$ 7,957	$ 6,394	$ 5,794
Capital expenditures						3,351	3,479	3,233
Ameren Illinois Company
Public Utilities, General Disclosures [Line Items]
Annual investment in energy-efficiency programs						120
Revenues						3,756	2,895	2,535
Capital expenditures						$ 1,601	$ 1,432	$ 1,447
Ameren Illinois Company \| Minimum
Public Utilities, General Disclosures [Line Items]
ICC required RTO cost benefit study duration						5 years
Ameren Illinois Company \| Maximum
Public Utilities, General Disclosures [Line Items]
ICC required RTO cost benefit study duration						10 years
Electric Distribution \| Ameren Illinois Company
Public Utilities, General Disclosures [Line Items]
Number of Performance Metrics \| numberOfProposedPerformanceMetrics						7
Requested Return on Equity Adjustment						0.24%
IETL \| Ameren Illinois Company
Public Utilities, General Disclosures [Line Items]
Energy Transition Assistance Fund Surcharge						$ 25
IETL \| Ameren Illinois Company \| Maximum
Public Utilities, General Disclosures [Line Items]
Energy Transition Assistance Fund Surcharge						$ 50
IETL \| Electric Distribution \| Ameren Illinois Company
Public Utilities, General Disclosures [Line Items]
Amortization Period						2 years
Amortization Start Date						1 year
Multi-Year Rate Plan Reconciliation Cap						105.00%
Rate Case Filing Frequency						4 years
IETL \| Electric Distribution \| Ameren Illinois Company \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Multi-year rate plan requested revenue requirement		$ 1,556	$ 1,477	$ 1,373	$ 1,282
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		$ 5,300	$ 5,000	$ 4,600	$ 4,300
Public Utilities, Approved Equity Capital Structure, Percentage	50.00%
Public Utilities, Requested Rate Increase (Decrease), Percentage					50.00%
Public Utilities, Requested Rate Increase (Decrease), Amount					$ 175
IETL \| Electric Distribution \| Ameren Illinois Company \| Minimum
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Rate Increase (Decrease), Percentage						50.00%
IETL \| Electricity, Generation \| Ameren Illinois Company
Public Utilities, General Disclosures [Line Items]
Capital expenditures						$ 20
Number of Solar Generation Pilot Projects \| windGenerationFacility						2
IEIMA revenue requirement reconciliation adjustment \| Ameren Illinois Company
Public Utilities, General Disclosures [Line Items]
Amortization Period						2 years
Final Rate Order \| Ameren Illinois Company
Public Utilities, General Disclosures [Line Items]
Electric Energy-Efficiency Revenue Requirement						$ 76
Renewable energy credits and zero emission credits \| Electricity, Generation \| Ameren Illinois Company
Public Utilities, General Disclosures [Line Items]
Revenues						$ 100
Pending Rate Case \| Natural gas \| Ameren Illinois Company \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Public Utilities, Requested Return on Equity, Percentage	10.70%
Public Utilities, Requested Equity Capital Structure, Percentage	53.99%
Rate Base	$ 2,900
Public Utilities, Requested Rate Increase (Decrease), Amount	160
Revenues	$ 77
IEIMA revenue requirement reconciliation adjustment \| Final Rate Order \| Electric Distribution \| Ameren Illinois Company
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Equity Capital Structure, Percentage						50.00%
Amortization Period						2 years
Public Utilities, Approved Rate Increase (Decrease), Amount						$ 61
FEJA energy-efficiency rider \| Final Rate Order \| Ameren Illinois Company
Public Utilities, General Disclosures [Line Items]
Public Utilities, Approved Rate Increase (Decrease), Amount						$ 15