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COMMITMENTS AND CONTINGENCIES - ENVIRONMENTAL MATTERS (Details) $ in Millions | 1 Months Ended | 3 Months Ended | 15 Months Ended |
--- | --- | --- | --- | ---
Apr. 30, 2019 degreecelsius | Dec. 31, 2018 change | Mar. 31, 2020 USD ($) generating_units States | Mar. 31, 2019 MW | Dec. 31, 2019 USD ($)
Manufactured gas plant remediation |  |  |  |  |
Regulatory assets |  |  | $ 3,578.8 |  | $ 3,527.6
Environmental remediation costs |  |  |  |  |
Manufactured gas plant remediation |  |  |  |  |
Regulatory assets |  |  | $ 686.4 |  | 685.5
Mercury and Air Toxics Standards | Electric |  |  |  |  |
Air quality |  |  |  |  |
Revisions to Mercury and Air Toxics Standards | change |  | 0 |  |  |
Climate Change | Electric |  |  |  |  |
Air quality |  |  |  |  |
Number of states challenging the ACE rule | States |  |  | 22 |  |
Company goal for percentage of carbon dioxide emissions reduction by 2030 |  |  |  | 40.00% |
Capacity of coal generation retired, in megawatts | MW |  |  |  | 1,800 |
Per mile rate of methane emission reduction |  |  | 30.00% |  |
Climate Change | Electric | Maximum |  |  |  |  |
Air quality |  |  |  |  |
Global temperature increases limit | degreecelsius | 2 |  |  |  |
Steam Electric Effluent Limitation Guidelines | Electric |  |  |  |  |
Water quality |  |  |  |  |
Number of generating units of OCPP and ERGS | generating_units |  |  | 6 |  |
Expected cost to achieve required emissions reductions |  |  | $ 60.0 |  |
Manufactured Gas Plant Remediation | Natural gas |  |  |  |  |
Manufactured gas plant remediation |  |  |  |  |
Reserves for future environmental remediation |  |  | 589.4 |  | 589.2
Manufactured Gas Plant Remediation | Natural gas | Environmental remediation costs |  |  |  |  |
Manufactured gas plant remediation |  |  |  |  |
Regulatory assets |  |  | $ 686.4 |  | $ 685.5

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