Regulatory Matters - Schedule of Utilities Rate Plans (CECONY-Gas) (Details) - USD ($)	12 Months Ended			36 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2028	Dec. 31, 2025	Dec. 31, 2022
Public Utilities, General Disclosures [Line Items]
Total operating revenues	$ 16,918,000,000	$ 15,256,000,000	$ 14,663,000,000
Revenue decoupling mechanisms	0	0	0		$ 0	$ 3,000,000
CECONY
Public Utilities, General Disclosures [Line Items]
Total operating revenues	15,651,000,000	14,129,000,000	13,476,000,000
CECONY | Gas
Public Utilities, General Disclosures [Line Items]
Percentage of revenue reserve					15.00%
Other earnings incentives	4,000,000	7,000,000	5,000,000
Revenue decoupling mechanisms	131,500,000	93,000,000	162,000,000		$ 131,500,000
Negative revenue adjustments	7,000,000	2,000,000	3,000,000
Regulatory reconciliations	1,000,000	29,000,000	12,000,000		1,000,000
Deferred regulatory asset (liability)	$ 49,200,000	31,500,000	15,500,000		$ 49,200,000
Authorized return on common equity					9.25%
Earnings sharing	9.75%				9.75%
Earnings sharing, threshold limit	$ 0	4,300,000	0
Common equity ratio					48.00%
CECONY | Gas | Protected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA					$ 679,000,000
CECONY | Gas | Over Fifteen Years
Public Utilities, General Disclosures [Line Items]
Shortfall in revenue					99,000,000
CECONY | Gas | Over Two Years
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA					32,000,000
CECONY | Gas | Over Two Years | Unprotected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA					42,000,000
CECONY | Gas | Annually | Unprotected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA					21,000,000
CECONY | Gas | Maximum
Public Utilities, General Disclosures [Line Items]
Retained earnings	65,000,000				65,000,000
CECONY | Gas | Gas Leak Backlog, Leak Prone Pipe and Service Terminations
Public Utilities, General Disclosures [Line Items]
Total operating revenues	$ 8,000,000	$ 3,000,000	$ 3,000,000
CECONY | Gas | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Percentage of revenue reserve				15.00%
Earnings sharing				9.90%
Common equity ratio				48.00%
Annual gas revenue requirement				$ 33,330,000
Recovery deferral (percent)				80.00%
Maximum deferral (percent)				15.00%
CECONY | Gas | Scenario, Forecast | Over Three Years
Public Utilities, General Disclosures [Line Items]
Annual gas revenue requirement				$ 100,000,000
CECONY | Gas | Scenario, Forecast | Maximum
Public Utilities, General Disclosures [Line Items]
Retained earnings				65,000,000
CECONY | Gas | Year 1
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 earnings adjustment mechanism incentives					18,000,000
Negative revenue adjustments					107,000,000
Average rate base					$ 9,647,000,000
Weighted average cost of capital (after-tax)					6.75%
Actual return on common equity, percent					9.00%
Cost of long-term debt			4.46%
CECONY | Gas | Year 1 | Protected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA					$ 9,000,000
CECONY | Gas | Year 1 | Over Fifteen Years
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount					187,000,000
Amount of cost recovery					45,000,000
CECONY | Gas | Year 1 | Over Two Years
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA					16,000,000
CECONY | Gas | Year 1 | Gas average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					10,466,000,000
CECONY | Gas | Year 1 | Advanced metering infrastructure (AMI)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					234,000,000
CECONY | Gas | Year 1 | Customer Service Systems (CSS)
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					2,000,000
CECONY | Gas | Year 1 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes				(46,000,000)
Amortizations to income of net regulatory (assets) and liabilities				90,000,000
Negative revenue adjustments				135,000,000
Average rate base				$ 11,485,000,000
Weighted average cost of capital (after-tax)				6.98%
Authorized return on common equity				9.40%
Cost of long-term debt				4.78%
Requested rate increase (decrease), amount				$ 28,000,000
Electric base rate percentage				2.01%
Potential offsetting credit adjustments				$ 12,000,000
Actual net expenses amount				1,500,000
CECONY | Gas | Year 1 | Scenario, Forecast | Protected Portion
Public Utilities, General Disclosures [Line Items]
Reflects regulatory liability amortization				48,000,000
CECONY | Gas | Year 1 | Scenario, Forecast | Unprotected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA				36,000,000
Reflects regulatory liability amortization				6,000,000
CECONY | Gas | Year 1 | Scenario, Forecast | Gas average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations				12,931,000,000
CECONY | Gas | Year 2
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 earnings adjustment mechanism incentives					20,000,000
Negative revenue adjustments					119,000,000
Average rate base					$ 10,428,000,000
Weighted average cost of capital (after-tax)					6.79%
Actual return on common equity, percent					9.82%
Cost of long-term debt		4.54%
CECONY | Gas | Year 2 | Protected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA					$ 10,000,000
CECONY | Gas | Year 2 | Over Fifteen Years
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount					187,000,000
Amount of cost recovery					78,000,000
CECONY | Gas | Year 2 | Over Two Years
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA					16,000,000
CECONY | Gas | Year 2 | Gas average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					11,442,000,000
CECONY | Gas | Year 2 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes				170,000,000
Amortizations to income of net regulatory (assets) and liabilities				88,000,000
Negative revenue adjustments				143,000,000
Average rate base				$ 12,050,000,000
Weighted average cost of capital (after-tax)				7.04%
Cost of long-term debt				4.90%
Requested rate increase (decrease), amount				$ 69,000,000
Potential offsetting credit adjustments				13,000,000
Actual net expenses amount				2,250,000
CECONY | Gas | Year 2 | Scenario, Forecast | Protected Portion
Public Utilities, General Disclosures [Line Items]
Reflects regulatory liability amortization				46,000,000
CECONY | Gas | Year 2 | Scenario, Forecast | Unprotected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA				36,000,000
Reflects regulatory liability amortization				6,000,000
CECONY | Gas | Year 2 | Scenario, Forecast | Gas average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations				13,472,000,000
CECONY | Gas | Year 3
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 earnings adjustment mechanism incentives					21,000,000
Negative revenue adjustments					130,000,000
Average rate base					$ 11,063,000,000
Weighted average cost of capital (after-tax)					6.85%
Actual return on common equity, percent					9.45%
Cost of long-term debt	4.64%				4.64%
CECONY | Gas | Year 3 | Protected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA					$ 10,000,000
CECONY | Gas | Year 3 | Over Fifteen Years
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount					187,000,000
Amount of cost recovery					62,000,000
CECONY | Gas | Year 3 | Gas average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations					$ 12,142,000,000
CECONY | Gas | Year 3 | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Base rate changes				93,000,000
Amortizations to income of net regulatory (assets) and liabilities				86,000,000
Negative revenue adjustments				152,000,000
Average rate base				$ 12,615,000,000
Weighted average cost of capital (after-tax)				7.10%
Cost of long-term debt				5.01%
Requested rate increase (decrease), amount				$ 70,000,000
Potential offsetting credit adjustments				14,000,000
Actual net expenses amount				3,000,000
CECONY | Gas | Year 3 | Scenario, Forecast | Protected Portion
Public Utilities, General Disclosures [Line Items]
Reflects regulatory liability amortization				45,000,000
CECONY | Gas | Year 3 | Scenario, Forecast | Unprotected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA				36,000,000
Reflects regulatory liability amortization				5,000,000
CECONY | Gas | Year 3 | Scenario, Forecast | Gas average excluding AMI
Public Utilities, General Disclosures [Line Items]
Net utility plant reconciliations				$ 14,014,000,000