Regulatory Matters - Other Regulatory Matters (Details) customer in Thousands, $ in Millions		1 Months Ended					6 Months Ended	9 Months Ended	12 Months Ended				36 Months Ended
	Jan. 01, 2022 USD ($)	Jul. 31, 2021 USD ($)	Jan. 31, 2021 USD ($)	Nov. 30, 2020 USD ($) claim	Aug. 31, 2020 USD ($) customer	Jul. 31, 2019 USD ($) customer	Jun. 30, 2021 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2022 USD ($)
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities									$ 4,381.0	$ 4,513.0
Other customer-provided capital rate									1.80%	2.65%
Return on regulatory assets									$ 1,962.0	$ 1,639.0
Net unbilled revenue deferrals
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities									209.0	198.0
RECO
Public Utilities, General Disclosures [Line Items]
Return on regulatory assets									25.0	31.0
RECO | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Restoration costs									11.4
Operation and maintenance expenses charged against a storm reserve									7.6
Capital expenditures					$ 2.5
Food and medicine spoilage expense					$ 1.3
CECONY
Public Utilities, General Disclosures [Line Items]
Net regulatory assets									1,176.0	1,200.0
Regulatory liabilities									3,921.0	4,094.0
Return on regulatory assets									$ 1,751.0	1,454.0
CECONY | Commodity
Public Utilities, General Disclosures [Line Items]
Regulatory assets, recovery period									4 years
CECONY | Net unbilled revenue deferrals
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities									$ 209.0	198.0
CECONY | Electric | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA			$ 377.0
CECONY | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Number of customers affected with interrupted service | customer					330
Litigation settlement, amount awarded to other party		$ 75.1
Litigation settlement, period		35 years
Estimate of possible loss				$ 102.3
Restoration costs					$ 174.0
Operation and maintenance expenses charged against a storm reserve					84.0
Capital expenditures					64.0
Operation and maintenance expenses									26.0
Food and medicine spoilage expense					$ 7.5
Alleged number of claims, violations | claim				33
CECONY | Electric | Protected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA			1,663.0
CECONY | Electric | Unprotected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA			784.0
CECONY | Electric | Scenario, Forecast | Subsidiaries
Public Utilities, General Disclosures [Line Items]
TCJA, net benefit amortization, allocation period													3 years
CECONY | Electric | Scenario, Forecast | Protected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA													$ 1,663.0
CECONY | Electric | Scenario, Forecast | Unprotected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA													$ 784.0
CECONY | Electric | Scenario, Forecast | Unprotected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
TCJA, net benefit amortization, allocation period													5 years
CECONY | Gas | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA			63.0
CECONY | Gas | Protected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA			725.0
CECONY | Gas | Unprotected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA			$ 107.0
CECONY | Gas | Scenario, Forecast | Subsidiaries
Public Utilities, General Disclosures [Line Items]
TCJA, net benefit amortization, allocation period													2 years
CECONY | Gas | Scenario, Forecast | Protected Portion
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA													$ 725.0
CECONY | Gas | Scenario, Forecast | Unprotected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
TCJA, net benefit amortization, allocation period													5 years
CECONY | NYSPSC | Steam | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA								$ 185.0
O&R
Public Utilities, General Disclosures [Line Items]
Net regulatory assets									$ 26.0	$ 29.0
O&R | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Number of customers affected with interrupted service | customer					200
Litigation settlement, amount awarded to other party		$ 7.0
Property damage, clean up and response costs					$ 1.6
Estimate of possible loss				$ 19.0
Restoration costs					26.5
Operation and maintenance expenses charged against a storm reserve					19.2
Capital expenditures					$ 5.7
Alleged number of claims, violations | claim				38
O&R | Electric and Gas | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA												$ 22.0
O&R | Electric and Gas | Protected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Increase in regulatory liability resulting from TCJA												$ 123.0
O&R | Electric and Gas | Scenario, Forecast | Subsidiaries
Public Utilities, General Disclosures [Line Items]
TCJA, net benefit amortization, allocation period													3 years
O&R | Electric and Gas | Scenario, Forecast | Unprotected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
TCJA, net benefit amortization, allocation period	6 years
Increase in regulatory liability resulting from TCJA	$ 34.0
Manhattan | CECONY | Electric | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Number of customers affected with interrupted service | customer					190	72
Estimate of possible loss						$ 24.8
Brooklyn | CECONY | Electric
Public Utilities, General Disclosures [Line Items]
Cumulative catch-up adjustment to revenue, modification of contract											$ (15.0)
Brooklyn | CECONY | Electric | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Number of customers affected with interrupted service | customer						30
Foregone Customer Recovery | CECONY | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Litigation settlement, amount awarded to other party		25.0
Foregone Customer Recovery | O&R | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Litigation settlement, amount awarded to other party		2.5
Ongoing Operations And Maintenance Costs | CECONY | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Litigation settlement, amount awarded to other party		15.8
Ongoing Operations And Maintenance Costs | O&R | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Litigation settlement, amount awarded to other party		2.9
Previously Incurred Or Accrued Costs | CECONY | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Litigation settlement, amount awarded to other party		34.3
Previously Incurred Or Accrued Costs | O&R | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Litigation settlement, amount awarded to other party		1.6
Negative Revenue Adjustment | CECONY | Electric | Rainey Outages | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Litigation settlement, amount awarded to other party		5.0
Negative Revenue Adjustment | CECONY | Electric | 2019 Manhattan and Brooklyn Outages | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Litigation settlement, amount awarded to other party		15.0
Costs To Reimburse Customers For Food And Medicine Spoilage | CECONY | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Litigation settlement, amount awarded to other party		$ 14.3
Manhattan Steam Main Rupture | CECONY | NYSPSC | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Property damage, clean up and response costs							$ 17.0
Capital and retirement costs							9.0
Loss contingency accrual							$ 3.0