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- Definition

Estimated capital costs to comply with existing and known federal and state air emissions regulations

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Number of Ameren Missouri Natural Gas Energy Centers Subject To IETL emission standards.

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Number Of Remediation Sites

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Number of Energy Center Scrubbers to achieve compliance with regulations

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- Definition

Plant To Be Abandoned, Net

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- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

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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.

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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Commitments And Contingencies (Environmental Matters) (Details) $ in Millions	Dec. 31, 2023 USD ($) scrubber energyCenter site	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Asset Retirement Obligation	$ 791	$ 786	$ 764
Environmental Loss Contingency Statement Of Financial Position Extensible Enumeration Not Disclosed Flag	false
Coal Fired Electric Generation Equipment
Plant To Be Abandoned, Net	$ 530	582
Ameren Missouri
Number of Energy Center Scrubbers \| scrubber	2
Asset Retirement Obligation	$ 787	782	760
Number of Ameren Missouri Natural Gas Energy Centers Subject To IETL \| energyCenter	4
Ameren Missouri \| Coal Fired Electric Generation Equipment
Plant To Be Abandoned, Net	$ 530	582
Ameren Illinois
Asset Retirement Obligation	$ 4	4	$ 4
Number of remediation sites \| site	3
Ameren Illinois \| Coal Fired Electric Generation Equipment
Plant To Be Abandoned, Net	$ 0	$ 0
Manufactured Gas Plant
Accrual for environmental loss contingencies	$ 51
Manufactured Gas Plant \| Ameren Illinois
Number of remediation sites \| site	44
Minimum
Estimated capital costs to comply with existing and known federal and state air emissions regulations	$ 90
Minimum \| Ameren Missouri
Estimated capital costs to comply with existing and known federal and state air emissions regulations	90
Minimum \| Manufactured Gas Plant \| Ameren Illinois
Estimate of possible loss	51
Maximum
Estimated capital costs to comply with existing and known federal and state air emissions regulations	120
Maximum \| Ameren Missouri
Estimated capital costs to comply with existing and known federal and state air emissions regulations	120
Maximum \| Manufactured Gas Plant \| Ameren Illinois
Estimate of possible loss	96
New CCR Rules Estimate
Asset Retirement Obligation	40
New CCR Rules Estimate \| Ameren Missouri
Asset Retirement Obligation	$ 40