Regulatory Matters - Summary of Utilities Rate Plans (CECONY-Electric) (Details) - USD ($)	1 Months Ended					12 Months Ended						36 Months Ended
	Jan. 31, 2025	Jan. 31, 2024	Jan. 31, 2022	Nov. 30, 2021	Dec. 31, 2016	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2022	Dec. 31, 2019	Dec. 31, 2016	Dec. 31, 2024
Public Utilities, General Disclosures [Line Items]
Revenues						$ 13,676,000,000	$ 12,246,000,000	$ 12,574,000,000
Deferred revenues						7,000,000	41,000,000	17,000,000	$ 20,000,000				$ 17,000,000
Deferred revenues						$ (662,000,000)	(599,000,000)
NYSPSC
Public Utilities, General Disclosures [Line Items]
Percentage of total consolidated revenues						15.00%
Maximum | NYSPSC
Public Utilities, General Disclosures [Line Items]
Percentage of total consolidated revenues						15.00%
Percentage of debt to total consolidated debt						20.00%
CECONY
Public Utilities, General Disclosures [Line Items]
Revenues						$ 11,716,000,000	10,647,000,000	10,821,000,000
Deferred revenues						(549,000,000)	(523,000,000)
CECONY | Electric
Public Utilities, General Disclosures [Line Items]
Retention of annual transmission congestion revenues													75,000,000
Actual earnings adjustment mechanism incentives						64,000,000	34,000,000	43,000,000	25,000,000	$ 13,000,000
Other earnings incentives								5,000,000	5,000,000	5,000,000
Deferred revenues						226,000,000	242,000,000	169,000,000	(6,000,000)	45,000,000			169,000,000
Negative revenue adjustments						0	5,000,000	15,000,000	0	0
Cost reconciliation, deferred net regulatory liabilities						191,000,000	288,000,000	10,000,000	189,000,000	35,000,000			10,000,000
Deferred regulatory asset (liability)						3,200,000	4,100,000	(11,800,000)	(400,000)	400,000			$ (11,800,000)
Earnings sharing, threshold limit							$ 0	0		$ 0
Earnings sharing, positive adjustment						$ 4,300,000					$ 5,700,000
Common equity ratio, percentage													48.00%
Increase in gas base rate due to expiration of temporary credit under the prior rate plan					$ 48,000,000
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)						30.00%
CECONY | Electric | NYSPSC
Public Utilities, General Disclosures [Line Items]
Base rate changes						$ 199,000,000
Actual return on common equity (percent)							8.81%
Amount of cost recovery				$ 43,000,000		19,000,000	$ 43,000,000
CECONY | Electric | NYSPSC | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount			$ 1,199,000,000
Return on common equity (percent)			10.00%
Common equity ratio			50.00%
CECONY | Electric | Service Termination
Public Utilities, General Disclosures [Line Items]
Revenues								$ 7,000,000	$ 3,000,000
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)												8.80%
Earnings sharing (percent)															9.30%
Common equity ratio, percentage												48.00%
Maximum deferral (percent)															15.00%
CECONY | Electric | Scenario, Forecast | NYSPSC
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount	$ 608,000,000	$ 853,000,000
Return on common equity (percent)		10.00%
Common equity ratio		50.00%
CECONY | Electric | Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes						$ 195,000,000
Utilities operating expense, depreciation and amortization													$ 84,000,000
Potential earnings adjustment mechanism incentives													28,000,000
Average rate base													$ 18,902,000,000
Weighted average cost of capital (after-tax) (percent)													6.82%
Authorized return on common equity (percent)													9.00%
Actual return on common equity (percent)													9.30%
Earnings sharing (percent)						9.50%
Cost of long-term debt rate						4.93%
Recovery of energy efficiency and savings program costs													$ 20,500,000
Deferral, annual maximum (not more than) (percent)														10.00%
CECONY | Electric | Year 1 | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations													21,689,000,000
CECONY | Electric | Year 1 | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations													126,000,000
CECONY | Electric | Year 1 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)													376,000,000
CECONY | Electric | Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes															$ 113,000,000
Utilities operating expense, depreciation and amortization												$ 267,000,000
Potential earnings adjustment mechanism incentives												69,000,000
Potential penalties (annually)												450,000,000
Average rate base												$ 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%
Amount of cost recovery												$ 206,000,000
CECONY | Electric | Year 1 | Scenario, Forecast | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations												24,491,000,000
CECONY | Electric | Year 1 | Scenario, Forecast | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations												572,000,000
CECONY | Electric | Year 2
Public Utilities, General Disclosures [Line Items]
Base rate changes						$ 155,000,000
Utilities operating expense, depreciation and amortization													83,000,000
Potential earnings adjustment mechanism incentives													47,000,000
Average rate base													$ 19,530,000,000
Weighted average cost of capital (after-tax) (percent)													6.80%
Actual return on common equity (percent)													9.36%
Cost of long-term debt rate						4.88%
Recovery of energy efficiency and savings program costs													$ 49,000,000
Deferral, annual maximum (not more than) (percent)														7.50%
CECONY | Electric | Year 2 | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations													22,338,000,000
CECONY | Electric | Year 2 | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations													257,000,000
CECONY | Electric | Year 2 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)													341,000,000
CECONY | Electric | Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes															$ 370,000,000
Utilities operating expense, depreciation and amortization												269,000,000
Potential earnings adjustment mechanism incentives												74,000,000
Potential penalties (annually)												461,000,000
Average rate base												$ 22,783,000,000
Actual return on common equity (percent)												8.03%
Amount of cost recovery												$ 245,000,000
CECONY | Electric | Year 2 | Scenario, Forecast | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations												25,092,000,000
CECONY | Electric | Year 2 | Scenario, Forecast | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations												740,000,000
CECONY | Electric | Year 3
Public Utilities, General Disclosures [Line Items]
Base rate changes						$ 155,000,000
Utilities operating expense, depreciation and amortization													69,000,000
Potential earnings adjustment mechanism incentives													64,000,000
Average rate base													$ 20,277,000,000
Weighted average cost of capital (after-tax) (percent)													6.73%
Actual return on common equity (percent)													8.82%
Cost of long-term debt rate						4.74%
Recovery of energy efficiency and savings program costs													$ 107,500,000
Deferral, annual maximum (not more than) (percent)														5.00%
CECONY | Electric | Year 3 | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations													23,002,000,000
CECONY | Electric | Year 3 | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations													415,000,000
CECONY | Electric | Year 3 | Maximum
Public Utilities, General Disclosures [Line Items]
Potential penalties (annually)													$ 352,000,000
CECONY | Electric | Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes															$ 326,000,000
Utilities operating expense, depreciation and amortization												272,000,000
Potential earnings adjustment mechanism incentives												79,000,000
Potential penalties (annually)												476,000,000
Average rate base												23,926,000,000
Amount of cost recovery												251,000,000
CECONY | Electric | Year 3 | Scenario, Forecast | Electric average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations												25,708,000,000
CECONY | Electric | Year 3 | Scenario, Forecast | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations												806,000,000
Annually | CECONY | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA												126,000,000
Annually | CECONY | Electric | Scenario, Forecast | Deferred Project Costs
Public Utilities, General Disclosures [Line Items]
Utilities operating expense, depreciation and amortization												48,000,000
Over Five Years | CECONY | Electric | Scenario, Forecast | Deferred Project Costs
Public Utilities, General Disclosures [Line Items]
Utilities operating expense, depreciation and amortization												238,000,000
Over Three Years | CECONY | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA												377,000,000
Protected Portion | CECONY | Electric | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA												1,663,000,000
Protected Portion | CECONY | Electric | Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA												49,000,000
Protected Portion | CECONY | Electric | Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA												50,000,000
Protected Portion | CECONY | Electric | Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA												53,000,000
Unprotected Portion | CECONY | Electric | Scenario, Forecast
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 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA												$ 157,000,000