Regulatory Matters - Summary of Utilities Rate Plans (CECONY-Gas) (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]
Cost of services provided		$ 14,663,000,000	$ 15,670,000,000	$ 13,676,000,000
Deferred regulatory liabilities		0	3,000,000	7,000,000	$ 41,000,000		$ 3,000,000
CECONY
Public Utilities, General Disclosures [Line Items]
Cost of services provided		13,476,000,000	13,268,000,000	11,716,000,000
CECONY | Gas
Public Utilities, General Disclosures [Line Items]
Percentage of revenue reserve							15.00%
Other earnings incentives		5,000,000	8,000,000	26,000,000	3,000,000
Deferred regulatory liabilities		162,000,000	141,000,000	100,000,000	27,000,000		$ 141,000,000
Negative revenue adjustments			8,000,000	3,000,000	3,000,000
Cost reconciliation, deferred net regulatory liabilities		12,000,000	70,000,000	14,000,000	91,000,000		70,000,000
Deferred regulatory asset (liability)		(15,500,000)	10,800,000	$ (26,000,000)	(24,700,000)		$ 10,800,000
Authorized return on common equity (percent)							8.80%
Earnings sharing (percent)				9.30%
Earnings sharing, threshold limit			0	$ 0	0
CECONY | Gas | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Percentage of revenue reserve						15.00%
Earnings sharing (percent)						9.75%
Common equity ratio (percent)						48.00%
CECONY | Gas | Maximum
Public Utilities, General Disclosures [Line Items]
Amount of revenues retained			65,000,000				$ 65,000,000
CECONY | Gas | Maximum | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Amount of revenues retained						$ 65,000,000
CECONY | Gas | Gas Leak Backlog, Leak Prone Pipe and Service Terminations
Public Utilities, General Disclosures [Line Items]
Cost of services provided		$ 3,000,000	$ 9,000,000	7,000,000	$ 13,000,000
CECONY | Gas | Service Termination
Public Utilities, General Disclosures [Line Items]
Incentives reversed				6,000,000
CECONY | Gas | Rate Plan for Year 1
Public Utilities, General Disclosures [Line Items]
Base rate changes							84,000,000
Amortizations to income of net regulatory (assets) and liabilities							45,000,000
Potential incentives if performance targets are met							20,000,000
Potential penalties (annually)							81,000,000
Weighted average cost of capital (after-tax)							$ 7,171,000,000
Weighted average cost of capital (after-tax) (percent)							6.61%
Actual return on common equity (percent)							8.40%
Cost of long-term debt rate			4.63%				4.63%
CECONY | Gas | Rate Plan for Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes						217,000,000
Amortizations to income of net regulatory (assets) and liabilities						31,000,000
Potential incentives if performance targets are met						18,000,000
Potential penalties (annually)						107,000,000
Weighted average cost of capital (after-tax)						$ 9,647,000,000
Weighted average cost of capital (after-tax) (percent)						6.75%
Authorized return on common equity (percent)						9.25%
Actual return on common equity (percent)						9.00%
Cost of long-term debt rate						4.46%
CECONY | Gas | Rate Plan for Year 1 | Gas average excluding AMI
Public Utilities, General Disclosures [Line Items]
Average rate base							$ 8,108,000,000
CECONY | Gas | Rate Plan for Year 1 | Gas average excluding AMI | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Average rate base						$ 10,466,000,000
CECONY | Gas | Rate Plan for Year 1 | AMI
Public Utilities, General Disclosures [Line Items]
Average rate base							142,000,000
CECONY | Gas | Rate Plan for Year 1 | AMI | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Average rate base						234,000,000
CECONY | Gas | Rate Plan for Year 1 | Customer Service Systems (CSS) | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Average rate base						2,000,000
CECONY | Gas | Rate Plan for Year 2
Public Utilities, General Disclosures [Line Items]
Base rate changes							122,000,000
Amortizations to income of net regulatory (assets) and liabilities							43,000,000
Potential incentives if performance targets are met							22,000,000
Potential penalties (annually)							88,000,000
Weighted average cost of capital (after-tax)							$ 7,911,000,000
Weighted average cost of capital (after-tax) (percent)							6.61%
Actual return on common equity (percent)							8.48%
Cost of long-term debt rate			4.63%				4.63%
CECONY | Gas | Rate Plan for Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes						173,000,000
Amortizations to income of net regulatory (assets) and liabilities						24,000,000
Potential incentives if performance targets are met						20,000,000
Potential penalties (annually)						119,000,000
Weighted average cost of capital (after-tax)						$ 10,428,000,000
Weighted average cost of capital (after-tax) (percent)						6.79%
Cost of long-term debt rate						4.54%
CECONY | Gas | Rate Plan for Year 2 | Gas average excluding AMI
Public Utilities, General Disclosures [Line Items]
Average rate base							$ 8,808,000,000
CECONY | Gas | Rate Plan for Year 2 | Gas average excluding AMI | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Average rate base						$ 11,442,000,000
CECONY | Gas | Rate Plan for Year 2 | AMI
Public Utilities, General Disclosures [Line Items]
Average rate base							183,000,000
CECONY | Gas | Rate Plan for Year 3
Public Utilities, General Disclosures [Line Items]
Base rate changes							167,000,000
Amortizations to income of net regulatory (assets) and liabilities							10,000,000
Potential incentives if performance targets are met							25,000,000
Potential penalties (annually)							96,000,000
Weighted average cost of capital (after-tax)							$ 8,622,000,000
Weighted average cost of capital (after-tax) (percent)							6.61%
Actual return on common equity (percent)							8.93%
Cost of long-term debt rate			4.63%				4.63%
CECONY | Gas | Rate Plan for Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes						122,000,000
Amortizations to income of net regulatory (assets) and liabilities						(11,000,000)
Potential incentives if performance targets are met						21,000,000
Potential penalties (annually)						130,000,000
Weighted average cost of capital (after-tax)						$ 11,063,000,000
Weighted average cost of capital (after-tax) (percent)						6.85%
Cost of long-term debt rate						4.64%
CECONY | Gas | Rate Plan for Year 3 | Gas average excluding AMI
Public Utilities, General Disclosures [Line Items]
Average rate base							$ 9,510,000,000
CECONY | Gas | Rate Plan for Year 3 | Gas average excluding AMI | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Average rate base						$ 12,142,000,000
CECONY | Gas | Rate Plan for Year 3 | AMI
Public Utilities, General Disclosures [Line Items]
Average rate base							211,000,000
NYSPSC | CECONY | Gas
Public Utilities, General Disclosures [Line Items]
Actual return on common equity (percent)					8.56%
Amount of cost recovery	$ 7,000,000			$ 11,000,000
Annually | CECONY | Gas
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA							32,000,000
Annually | CECONY | Gas | Rate Plan for Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA						16,000,000
Annually | CECONY | Gas | Rate Plan for Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA						16,000,000
Over Ten Years | CECONY | Gas | Rate Plan for Year 1
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount							47,000,000
Amount of cost recovery							30,000,000
Over Ten Years | CECONY | Gas | Rate Plan for Year 2
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount							176,000,000
Amount of cost recovery							37,000,000
Over Ten Years | CECONY | Gas | Rate Plan for Year 3
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount							170,000,000
Amount of cost recovery							40,000,000
Over Two Years | CECONY | Gas
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA							63,000,000
Over Two Years | CECONY | Gas | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA						32,000,000
Over Fifteen Years | CECONY | Gas | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Shortfall in revenue						99,000,000
Over Fifteen Years | CECONY | Gas | Rate Plan for Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						187,000,000
Amount of cost recovery						45,000,000
Over Fifteen Years | CECONY | Gas | Rate Plan for Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						187,000,000
Amount of cost recovery						78,000,000
Over Fifteen Years | CECONY | Gas | Rate Plan for Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount						187,000,000
Amount of cost recovery						62,000,000
Protected Portion | CECONY | Gas
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							725,000,000
Protected Portion | CECONY | Gas | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						679,000,000
Protected Portion | CECONY | Gas | Rate Plan for Year 1
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							14,000,000
Protected Portion | CECONY | Gas | Rate Plan for Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						9,000,000
Protected Portion | CECONY | Gas | Rate Plan for Year 2
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							14,000,000
Protected Portion | CECONY | Gas | Rate Plan for Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						10,000,000
Protected Portion | CECONY | Gas | Rate Plan for Year 3
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							12,000,000
Protected Portion | CECONY | Gas | Rate Plan for Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						10,000,000
Unprotected Portion | Annually | CECONY | Gas
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							21,000,000
Unprotected Portion | Annually | CECONY | Gas | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						21,000,000
Unprotected Portion | Over Two Years | CECONY | Gas | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA						$ 42,000,000
Unprotected Portion | Over Five Years | CECONY | Gas
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA							$ 107,000,000