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Environmental Matters - Additional Information (Details) - USD ($) $ in Billions | 9 Months Ended |
--- | --- | ---
Sep. 30, 2020 | Dec. 31, 2019
CECONY | Asbestos Proceedings |  |
Site Contingency [Line Items] |  |
Estimated undiscounted asbestos liability (years) | 15 years |
Superfund Sites | Manufactured Gas Plant Sites | Maximum |  |
Site Contingency [Line Items] |  |
Estimated aggregate undiscounted potential liability related environmental contaminants (up to) |  | $ 2.8
Superfund Sites | Manufactured Gas Plant Sites | Maximum | CECONY |  |
Site Contingency [Line Items] |  |
Estimated aggregate undiscounted potential liability related environmental contaminants (up to) |  | $ 2.6

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