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Commitments And Contingencies (Environmental Matters) (Details) $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2022 USD ($) energyCenter scrubber site | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($)
Asset Retirement Obligation | $ 786 | $ 764 | $ 756
Coal Fired Electric Generation Equipment |  |  |
Plant To Be Abandoned, Net | $ 582 | 604 |
Union Electric Company |  |  |
Number of Energy Center Scrubbers | scrubber | 2 |  |
Number of Energy Centers Constructing Wastewater Treatment Facilities | energyCenter | 3 |  |
Number of Energy Centers | energyCenter | 4 |  |
Asset Retirement Obligation | $ 782 | 760 | 751
Number of Ameren Missouri Natural Gas Energy Centers Subject To IETL | energyCenter | 4 |  |
Union Electric Company | Coal Fired Electric Generation Equipment |  |  |
Plant To Be Abandoned, Net | $ 582 | 604 |
Ameren Illinois Company |  |  |
Asset Retirement Obligation | 4 | 4 | $ 5
Ameren Illinois Company | Coal Fired Electric Generation Equipment |  |  |
Plant To Be Abandoned, Net | 0 | $ 0 |
Manufactured Gas Plant |  |  |
Accrual for environmental loss contingencies | $ 63 |  |
Manufactured Gas Plant | Ameren Illinois Company |  |  |
Number of remediation sites | site | 44 |  |
Accrual for environmental loss contingencies | $ 63 |  |
Minimum |  |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | 90 |  |
Minimum | Union Electric Company |  |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | 90 |  |
Minimum | Coal Combustion Residuals Estimate | Union Electric Company |  |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | 30 |  |
Minimum | Manufactured Gas Plant | Ameren Illinois Company |  |  |
Estimate of possible loss | 63 |  |
Maximum |  |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | 120 |  |
Maximum | Union Electric Company |  |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | 120 |  |
Maximum | Coal Combustion Residuals Estimate | Union Electric Company |  |  |
Estimated capital costs to comply with existing and known federal and state air emissions regulations | 50 |  |
Maximum | Manufactured Gas Plant | Ameren Illinois Company |  |  |
Estimate of possible loss | 145 |  |
Rush Island Energy Center | Union Electric Company |  |  |
Rate Base | 400 |  |
New CCR Rules Estimate |  |  |
Asset Retirement Obligation | 49 |  |
New CCR Rules Estimate | Union Electric Company |  |  |
Asset Retirement Obligation | $ 49 |  |

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