Capitalization - Additional Information (Details) - USD ($)	1 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Apr. 30, 2018	Dec. 31, 2018	Aug. 31, 2018	May 31, 2018
CECONY
Schedule of Capitalization [Line Items]
Tax-exempt debt		$ 636,000,000
CECONY | Debentures | 5.85% Debentures
Schedule of Capitalization [Line Items]
Face amount of debt			$ 600,000,000
Interest rate			5.85%
Debt term			10 years
CECONY | Debentures | 3.80% Debentures
Schedule of Capitalization [Line Items]
Face amount of debt						$ 300,000,000
Interest rate						3.80%
CECONY | Debentures | 4.50% Debentures
Schedule of Capitalization [Line Items]
Face amount of debt						$ 700,000,000
Interest rate						4.50%
CECONY | Debentures | Floating Rate Debentures
Schedule of Capitalization [Line Items]
Face amount of debt		$ 640,000,000
O&R | Debentures | 4.35% Debentures
Schedule of Capitalization [Line Items]
Face amount of debt					$ 125,000,000
Interest rate					4.35%
O&R | Debentures | 4.35% Debentures | Scenario, Forecast
Schedule of Capitalization [Line Items]
Face amount of debt				$ 25,000,000
O&R | Debentures | 6.15% Debentures
Schedule of Capitalization [Line Items]
Interest rate	6.15%
Debt term	10 years
Amount of debt redeemed	$ 50,000,000
Con Edison Development | Senior Notes | 4.41% Senior Notes Due 2028
Schedule of Capitalization [Line Items]
Face amount of debt	$ 140,000,000
Interest rate	4.41%