Regulatory Matters - Rate Plans (Details) - USD ($) $ in Millions		1 Months Ended									3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2021	Jan. 31, 2025	Jan. 31, 2024	Jan. 31, 2023	May 31, 2022	Apr. 30, 2022	Mar. 31, 2022	Jan. 31, 2022	Oct. 31, 2021	Jul. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Public Utilities, General Disclosures [Line Items]
Total revenues											$ 4,165.0	$ 3,613.0	$ 11,639.0	$ 10,261.0
Subsidiaries
Public Utilities, General Disclosures [Line Items]
Total revenues											$ 3,549.0	$ 3,092.0	9,972.0	$ 8,784.0
CECONY | Electric | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount					$ 278.0
Return on common equity (as a percent)					8.80%
Common equity ratio (percent)					48.00%
CECONY | Electric | Subsidiaries | Year 1
Public Utilities, General Disclosures [Line Items]
Change in requested rate increase (decrease), amount						$ 161.0
CECONY | Electric | Subsidiaries | Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount				$ 1,038.0
CECONY | Electric | Subsidiaries | Year 2
Public Utilities, General Disclosures [Line Items]
Change in requested rate increase (decrease), amount						109.0
CECONY | Electric | Subsidiaries | Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount			$ 744.0
CECONY | Electric | Subsidiaries | Year 3
Public Utilities, General Disclosures [Line Items]
Change in requested rate increase (decrease), amount						7.0
CECONY | Electric | Subsidiaries | Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount		$ 615.0
CECONY | Gas | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount					$ 164.0
Return on common equity (as a percent)					8.80%
Common equity ratio (percent)					48.00%
CECONY | Gas | Subsidiaries | Year 1
Public Utilities, General Disclosures [Line Items]
Change in requested rate increase (decrease), amount						101.0
CECONY | Gas | Subsidiaries | Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount				$ 402.0
CECONY | Gas | Subsidiaries | Year 2
Public Utilities, General Disclosures [Line Items]
Change in requested rate increase (decrease), amount						29.0
CECONY | Gas | Subsidiaries | Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount			$ 205.0
CECONY | Gas | Subsidiaries | Year 3
Public Utilities, General Disclosures [Line Items]
Change in requested rate increase (decrease), amount						42.0
CECONY | Gas | Subsidiaries | Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount		$ 176.0
CECONY | Electric and Gas Transmission Projects | Subsidiaries | Earnings Adjustment Mechanisms (EAMs)
Public Utilities, General Disclosures [Line Items]
Total revenues													$ (4.9)		$ 92.0
O&R | Electric | Year 1
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						4.9
O&R | Electric | Year 2
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						16.2
O&R | Electric | Year 3
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						23.1
O&R | Electric | Levelized Annual Basis
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						11.7
O&R | Gas | Year 1
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						0.7
O&R | Gas | Year 2
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						7.4
O&R | Gas | Year 3
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						9.9
O&R | Gas | Levelized Annual Basis
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						$ 4.4
O&R | Electric and Gas Transmission Projects
Public Utilities, General Disclosures [Line Items]
Recovery period of late payment charges									3 years
Recovery of late payment charges, amount									$ 2.8
Recovery of late payment charges, return on equity threshold rate									0.05%
RECO | Electric
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount	$ 16.9							$ 20.4
Return on common equity (percent)								11.04%		0.50%
Common equity ratio percentage								47.00%
RECO | NJBPU
Public Utilities, General Disclosures [Line Items]
Infrastructure investment plan							$ 209.0
Infrastructure investment plan period (in years)							5 years