Regulatory Matters - Summary of Utilities Rate Plans (CECONY-Electric) (Details) - USD ($)	1 Months Ended	12 Months Ended				36 Months Ended
	Nov. 30, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2025	Dec. 31, 2022
Public Utilities, General Disclosures [Line Items]
Deferred regulatory liabilities		$ 0	$ 3,000,000	$ 7,000,000	$ 41,000,000		$ 3,000,000
TOTAL OPERATING REVENUES		14,663,000,000	15,670,000,000	13,676,000,000
CECONY
Public Utilities, General Disclosures [Line Items]
TOTAL OPERATING REVENUES		13,476,000,000	13,268,000,000	11,716,000,000
CECONY | Electric
Public Utilities, General Disclosures [Line Items]
Retention of annual transmission congestion revenues							75,000,000
Actual earnings adjustment mechanism incentives		34,400,000	33,000,000	64,000,000	34,000,000
Deferred regulatory liabilities		162,000,000	90,000,000	226,000,000	242,000,000		90,000,000
Negative revenue adjustments		0	3,000,000	0	5,000,000
Cost reconciliation, deferred net regulatory liabilities		140,000,000	138,000,000	191,000,000	288,000,000		138,000,000
Deferred regulatory asset (liability)		$ 1,200,000	1,800,000	3,200,000	4,100,000		$ 1,800,000
Authorized return on common equity (percent)							8.80%
Earnings sharing (percent)		9.30%
Earnings sharing, threshold limit		$ 0	0	0	$ 0
Earnings sharing, positive adjustment				4,300,000
Common equity ratio (percent)							48.00%
Recovery or refund of energy costs, deferral period							10 years
Deferrals for property taxes limitation from rates (percent)							90.00%
Recovery deferral (percent)		80.00%
Maximum deferral (percent)		15.00%
CECONY | Electric | Gas Leak Backlog, Leak Prone Pipe and Service Terminations
Public Utilities, General Disclosures [Line Items]
TOTAL OPERATING REVENUES			4,000,000
CECONY | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Retention of annual transmission congestion revenues						$ 75,000,000
Authorized return on common equity (percent)						925.00%
Earnings sharing (percent)						9.75%
Common equity ratio (percent)						48.00%
CECONY | Electric | NYSPSC
Public Utilities, General Disclosures [Line Items]
Actual return on common equity (percent)					8.81%
Amount of cost recovery	$ 43,000,000			$ 62,000,000
CECONY | Electric | Rate Plan for Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes			113,000,000				$ 113,000,000
Amortizations to income of net regulatory (assets) and liabilities							267,000,000
Potential earnings adjustment mechanism incentives							69,000,000
Potential penalties (annually)							450,000,000
Weighted average cost of capital (after-tax)							$ 21,660,000,000
Weighted average cost of capital (after-tax) (percent)							6.61%
Actual return on common equity (percent)							8.50%
Cost of long-term debt rate		4.63%
Recovery of energy efficiency and savings program costs							$ 206,000,000
Deferral, annual maximum (not more than) (percent)							0.10%
CECONY | Electric | Rate Plan for Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes						$ 442,000,000
Amortizations to income of net regulatory (assets) and liabilities						104,000,000
Potential earnings adjustment mechanism incentives						70,000,000
Potential penalties (annually)						516,000,000
Weighted average cost of capital (after-tax)						$ 26,095,000,000
Weighted average cost of capital (after-tax) (percent)						6.75%
Actual return on common equity (percent)						9.46%
Cost of long-term debt rate						4.46%
Deferral, annual maximum (not more than) (percent)						0.10%
CECONY | Electric | Rate Plan for Year 1 | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations							$ 24,491,000,000
CECONY | Electric | Rate Plan for Year 1 | Electric average excluding AMI | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations						$ 27,847,000,000
CECONY | Electric | Rate Plan for Year 1 | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations							572,000,000
CECONY | Electric | Rate Plan for Year 1 | Advanced metering infrastructure (AMI) | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations						744,000,000
CECONY | Electric | Rate Plan for Year 1 | Customer Service Systems (CSS) | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations						11,000,000
CECONY | Electric | Rate Plan for Year 2
Public Utilities, General Disclosures [Line Items]
Base rate changes			370,000,000				370,000,000
Amortizations to income of net regulatory (assets) and liabilities							269,000,000
Potential earnings adjustment mechanism incentives							74,000,000
Potential penalties (annually)							461,000,000
Weighted average cost of capital (after-tax)							$ 22,783,000,000
Weighted average cost of capital (after-tax) (percent)							6.61%
Actual return on common equity (percent)							8.03%
Cost of long-term debt rate		4.63%
Recovery of energy efficiency and savings program costs							$ 245,000,000
Deferral, annual maximum (not more than) (percent)							0.075%
CECONY | Electric | Rate Plan for Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes						518,000,000
Amortizations to income of net regulatory (assets) and liabilities						49,000,000
Potential earnings adjustment mechanism incentives						75,000,000
Potential penalties (annually)						557,000,000
Weighted average cost of capital (after-tax)						$ 27,925,000,000
Weighted average cost of capital (after-tax) (percent)						6.79%
Cost of long-term debt rate						4.54%
Deferral, annual maximum (not more than) (percent)						0.05%
CECONY | Electric | Rate Plan for Year 2 | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations							$ 25,092,000,000
CECONY | Electric | Rate Plan for Year 2 | Electric average excluding AMI | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations						$ 29,884,000,000
CECONY | Electric | Rate Plan for Year 2 | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations							740,000,000
CECONY | Electric | Rate Plan for Year 3
Public Utilities, General Disclosures [Line Items]
Base rate changes			$ 326,000,000				326,000,000
Amortizations to income of net regulatory (assets) and liabilities							272,000,000
Potential earnings adjustment mechanism incentives							79,000,000
Potential penalties (annually)							476,000,000
Weighted average cost of capital (after-tax)							$ 23,926,000,000
Weighted average cost of capital (after-tax) (percent)							6.61%
Actual return on common equity (percent)							8.41%
Cost of long-term debt rate		4.63%
Recovery of energy efficiency and savings program costs							$ 251,000,000
Deferral, annual maximum (not more than) (percent)							0.05%
CECONY | Electric | Rate Plan for Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes						382,000,000
Amortizations to income of net regulatory (assets) and liabilities						(205,000,000)
Potential earnings adjustment mechanism incentives						79,000,000
Potential penalties (annually)						597,000,000
Weighted average cost of capital (after-tax)						$ 29,362,000,000
Weighted average cost of capital (after-tax) (percent)						6.85%
Cost of long-term debt rate						4.64%
Deferral, annual maximum (not more than) (percent)						0.05%
CECONY | Electric | Rate Plan for Year 3 | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations							$ 25,708,000,000
CECONY | Electric | Rate Plan for Year 3 | Electric average excluding AMI | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations						$ 31,026,000,000
CECONY | Electric | Rate Plan for Year 3 | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations							806,000,000
Annually | CECONY | Electric
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA							126,000,000
Annually | CECONY | Electric | Deferred Project Costs
Public Utilities, General Disclosures [Line Items]
Amortizations to income of net regulatory (assets) and liabilities							48,000,000
Annually | CECONY | Electric | Deferred Project Costs | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Amortizations to income of net regulatory (assets) and liabilities						31,000,000
Annually | CECONY | Electric | Rate Plan for Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA						128,000,000
Annually | CECONY | Electric | Rate Plan for Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA						128,000,000
Over Five Years | CECONY | Electric | Deferred Project Costs
Public Utilities, General Disclosures [Line Items]
Amortizations to income of net regulatory (assets) and liabilities							238,000,000
Over Three Years | CECONY | Electric
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA							377,000,000
Over Three Years | CECONY | Electric | Deferred Project Costs | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Amortizations to income of net regulatory (assets) and liabilities						93,000,000
Over Two Years | CECONY | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA						256,000,000
Over Seven To Fifteen Years | CECONY | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Shortfall in revenue						216,000,000
Over Seven To Fifteen Years | CECONY | Electric | Rate Plan for Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						457,000,000
Amount of cost recovery						244,000,000
Over Seven To Fifteen Years | CECONY | Electric | Rate Plan for Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						457,000,000
Amount of cost recovery						237,000,000
Over Seven To Fifteen Years | CECONY | Electric | Rate Plan for Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						457,000,000
Amount of cost recovery						281,000,000
Protected Portion | CECONY | Electric
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							1,663,000,000
Protected Portion | CECONY | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						1,512,000,000
Protected Portion | CECONY | Electric | Rate Plan for Year 1
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							49,000,000
Protected Portion | CECONY | Electric | Rate Plan for Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						34,000,000
Protected Portion | CECONY | Electric | Rate Plan for Year 2
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							50,000,000
Protected Portion | CECONY | Electric | Rate Plan for Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						63,000,000
Protected Portion | CECONY | Electric | Rate Plan for Year 3
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							53,000,000
Protected Portion | CECONY | Electric | Rate Plan for Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						34,000,000
Unprotected Portion | CECONY | Electric
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							$ 784,000,000
TCJA of 2017 regulatory liabilities, income tax benefit, amortization period							5 years
Unprotected Portion | Annually | CECONY | Electric
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							$ 157,000,000
Unprotected Portion | Annually | CECONY | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						153,000,000
Unprotected Portion | Over Two Years | CECONY | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						$ 306,000,000