XML 75 R36.htm IDEA: XBRL DOCUMENT
v3.22.2

Rate And Regulatory Matters (Narrative-Federal) (Details) - USD ($) $ in Millions | 1 Months Ended |  |
--- | --- | --- | ---
May 31, 2020 | Jun. 30, 2022 | Dec. 31, 2021
Rate And Regulatory Matters [Line Items] |  |  |
Regulatory liabilities |  | $ 5,727 | $ 5,848
Ameren Illinois Company |  |  |
Rate And Regulatory Matters [Line Items] |  |  |
Regulatory liabilities |  | 2,484 | $ 2,374
Final Rate Order | Ameren Illinois Company |  |  |
Rate And Regulatory Matters [Line Items] |  |  |
Regulatory liabilities |  | $ 9 |
Midwest Independent Transmission System Operator, Inc | Final Rate Order |  |  |
Rate And Regulatory Matters [Line Items] |  |  |
Approved return on equity percentage | 10.02% |  |

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 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 The amount for the individual regulatory noncurrent liability as itemized in a table of regulatory noncurrent liabilities as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.24) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_RegulatoryLiabilityNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

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

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=aee_MidwestIndependentTransmissionSystemOperatorIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |