Regulatory Matters - Rate Plans (Details) $ in Millions				1 Months Ended						2 Months Ended	36 Months Ended
	Jan. 01, 2024 USD ($)	Aug. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jul. 31, 2023 USD ($)	Apr. 30, 2023 USD ($) state	Mar. 31, 2023 USD ($)	Feb. 28, 2023 USD ($)	Nov. 30, 2022 USD ($)	Jan. 31, 2022 USD ($)	Apr. 30, 2023 USD ($) state	Dec. 31, 2022 USD ($)	May 31, 2023 USD ($)
Public Utilities, General Disclosures [Line Items]
Number of states | state					7					7
Brooklyn Clean Energy Hub
Public Utilities, General Disclosures [Line Items]
Estimated cost recovery					$ 810.0
CECONY
Public Utilities, General Disclosures [Line Items]
Federal grants applied for										$ 177.0
CECONY | Federal Grants Used For Carbon-Free Hydrogen
Public Utilities, General Disclosures [Line Items]
Federal grants applied for										116.0
CECONY | Electric | Year 1
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount											$ 457.0
CECONY | Electric | Year 1 | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount				$ 442.0
CECONY | Electric | Year 2
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount											457.0
CECONY | Electric | Year 2 | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount				518.0
CECONY | Electric | Year 3
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount											457.0
CECONY | Electric | Year 3 | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount				$ 382.0
CECONY | Electric | Subsidiaries | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Return on common equity (as a percent)				9.25%
Common equity ratio (percent)				48.00%
Capital expenditures				$ 8,513.0
CECONY | Gas | Year 1
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount											187.0
CECONY | Gas | Year 1 | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount				217.0
CECONY | Gas | Year 2
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount											187.0
CECONY | Gas | Year 2 | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount				173.0
CECONY | Gas | Year 3
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount											$ 187.0
CECONY | Gas | Year 3 | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount				122.0
CECONY | Gas | Subsidiaries | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Capital expenditures				$ 3,297.0
CECONY | Steam
Public Utilities, General Disclosures [Line Items]
Common equity ratio (percent)								50.00%
Requested rate increase (decrease), amount						$ 94.0
Deviation of actual inflation rate from assumed revenue requirement								0.0050
Return on common equity (percent)								10.00%
CECONY | Steam | Year 1
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount							$ 4.0
Total requested amount							141.0
CECONY | Steam | Year 2
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount							1.0	$ 54.0
Total requested amount							55.0
CECONY | Steam | Year 3
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount							4.0	$ 49.0
Total requested amount							$ 53.0
CECONY | Steam | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Return on common equity (as a percent)						9.00%
Common equity ratio (percent)						48.00%
CECONY | Electric and Gas Transmission Projects | Subsidiaries | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Rate plan, term (in years)				3 years
CECONY | NYSPSC | Steam
Public Utilities, General Disclosures [Line Items]
Return on common equity (as a percent)								10.00%
Common equity ratio (percent)								50.00%
Requested rate increase (decrease), amount								$ 137.0
RECO
Public Utilities, General Disclosures [Line Items]
Deferred costs												$ 5.1
RECO | Electric
Public Utilities, General Disclosures [Line Items]
Common equity ratio (percent)									47.00%
Requested rate increase (decrease), amount		$ 18.2	$ 16.9						$ 20.4
Return on common equity (percent)									11.04%
RECO | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount	$ 20.7
O&R
Public Utilities, General Disclosures [Line Items]
Federal grants applied for										$ 125.0