Regulatory Matters - COVID-19 Regulatory Matters (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)
CECONY
Public Utilities, General Disclosures [Line Items]
Earned EAM incentives		$ 46.0
O&R
Public Utilities, General Disclosures [Line Items]
Earned EAM incentives		3.0
COVID-19 | CECONY
Public Utilities, General Disclosures [Line Items]
Estimated forgone revenues	$ 20.0	1.2
COVID-19 | O&R
Public Utilities, General Disclosures [Line Items]
Estimated forgone revenues	23.0	1.4
Residential Customers | COVID-19 | CECONY
Public Utilities, General Disclosures [Line Items]
Deferred revenue	9.0	9.0
Expected deferred revenue	$ 58.0	58.0
Summer Cooling Credit Program | Residential Customers | COVID-19 | CECONY
Public Utilities, General Disclosures [Line Items]
Cost of the program		$ 70.6
Cost of the program, recovery period		5 years