Regulatory Matters - Additional Information (Details) - USD ($) $ in Millions		1 Months Ended			3 Months Ended		12 Months Ended
	Nov. 06, 2025	Nov. 30, 2027	Nov. 30, 2026	Nov. 30, 2025	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Public Utilities, General Disclosures [Line Items]
Rate adjustment mechanism					$ 0.5
Other customer-provided capital rate (in percent)					4.70%	4.75%
Return on regulatory assets					$ 3,763.0		$ 3,421.0
Deferred derivative losses recovery period, current (in years)					1 year
Recovery period for deferred derivative losses (in years)					3 years
Unrecognized pension and other postretirement costs period (in years)					10 years
Investment gains or losses is recognized in expense (in years)					15 years
CECONY
Public Utilities, General Disclosures [Line Items]
Annual gas revenue requirement amount	$ 33.3
Rate adjustment mechanism					$ 100.0
Net regulatory assets					1,031.0		1,049.0
Return on regulatory assets					$ 3,530.0		3,193.0
CECONY | Commodity
Public Utilities, General Disclosures [Line Items]
Recovery period (in years)					4 years
O&R
Public Utilities, General Disclosures [Line Items]
Net regulatory assets					$ 8.0		10.0
RECO
Public Utilities, General Disclosures [Line Items]
Return on regulatory assets					42.0		$ 41.0
Steam
Public Utilities, General Disclosures [Line Items]
Requested rate increase, amount					$ 18.0
Public utilities, requested return on equity (percentage)					9.30%
Common equity ratio (percent)					47.50%
Steam | CECONY
Public Utilities, General Disclosures [Line Items]
Requested rate increase, amount				$ 66.0
Public utilities, requested return on equity (percentage)				9.90%
Common equity ratio (percent)				48.00%
Steam | CECONY | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase, amount		$ 50.0	$ 50.0