Regulatory Matters - Other Regulatory Matters (Details) customer in Thousands, $ in Millions		1 Months Ended			3 Months Ended		6 Months Ended	9 Months Ended	36 Months Ended
	Jan. 01, 2022 USD ($)	Jul. 31, 2021 USD ($)	Aug. 31, 2020 customer	Jul. 31, 2019 customer	Mar. 31, 2022 USD ($)	Mar. 31, 2021	Jun. 30, 2021 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Public Utilities, General Disclosures [Line Items]
Other Customer-Provided Capital rate					1.75%	1.80%
Return on regulatory assets					$ 1,983.0		$ 1,962.0
Recovery period for deferred derivative losses					3 years
CECONY
Public Utilities, General Disclosures [Line Items]
Net regulatory assets					$ 1,165.0					$ 1,176.0
CECONY | Commodity
Public Utilities, General Disclosures [Line Items]
Recovery period					4 years
CECONY | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Return on regulatory assets					$ 1,777.0		1,751.0
CECONY | NYSPSC | Steam | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Impact in regulatory liability resulting from TCJA								$ 185.0
CECONY | Electric | West Side of Manhattan | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Number of customers affected with interrupted service | customer			190	72
CECONY | Electric | Brooklyn | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Number of customers affected with interrupted service | customer				30
CECONY | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Number of customers affected with interrupted service | customer			330
Settlement agreement, amount		$ 75.1
Litigation settlement, period					35 years
CECONY | Electric | Tropical Storm | Foregone Customer Recovery | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Settlement agreement, amount		25.0
CECONY | Electric | Tropical Storm | Ongoing Operations And Maintenance Costs | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Settlement agreement, amount		15.8
CECONY | Electric | Tropical Storm | Previously Incurred Or Accrued Costs | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Settlement agreement, amount		34.3
CECONY | Electric | Tropical Storm | Costs To Reimburse Customers For Food And Medicine Spoilage | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Settlement agreement, amount		14.3
CECONY | Electric | Rainey Outages | Negative Revenue Adjustment | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Settlement agreement, amount		5.0
CECONY | Electric | 2019 Manhattan and Brooklyn Outages | Negative Revenue Adjustment | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Settlement agreement, amount		15.0
CECONY | Electric | Scenario, Forecast | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA									$ 377.0
TCJA, net benefit amortization, allocation period									3 years
CECONY | Electric | Scenario, Forecast | Protected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Impact in regulatory liability resulting from TCJA									$ 1,663.0
CECONY | Electric | Scenario, Forecast | Unprotected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
TCJA, net benefit amortization, allocation period									5 years
Impact in regulatory liability resulting from TCJA									$ 784.0
CECONY | Gas | Scenario, Forecast | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA									$ 63.0
TCJA, net benefit amortization, allocation period									2 years
CECONY | Gas | Scenario, Forecast | Protected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Impact 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
Impact in regulatory liability resulting from TCJA									$ 107.0
O&R
Public Utilities, General Disclosures [Line Items]
Net regulatory assets					$ 25.0					$ 26.0
O&R | Electric | Tropical Storm | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Number of customers affected with interrupted service | customer			200
Settlement agreement, amount		7.0
O&R | Electric | Tropical Storm | Foregone Customer Recovery | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Settlement agreement, amount		2.5
O&R | Electric | Tropical Storm | Ongoing Operations And Maintenance Costs | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Settlement agreement, amount		2.9
O&R | Electric | Tropical Storm | Previously Incurred Or Accrued Costs | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Settlement agreement, amount		$ 1.6
O&R | Electric and Gas Transmission Projects | Unprotected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
TCJA, net benefit amortization, allocation period	6 years
Impact in regulatory liability resulting from TCJA	$ 34.0
O&R | Electric and Gas Transmission Projects | Scenario, Forecast | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Income tax benefit to be credited to customers resulting from TCJA									$ 22.0
TCJA, net benefit amortization, allocation period									3 years
O&R | Electric and Gas Transmission Projects | Scenario, Forecast | Protected Portion | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Impact in regulatory liability resulting from TCJA									$ 123.0
RECO | Subsidiaries
Public Utilities, General Disclosures [Line Items]
Return on regulatory assets					$ 22.0		$ 25.0