Income Tax - Schedule of Income Tax Reconciliation (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
STATUTORY TAX RATE
Federal	21.00%	21.00%	21.00%
Changes in computed taxes resulting from:
State income taxes, net of federal income taxes	5.00%	6.00%	4.00%
Taxes attributable to noncontrolling interests	0.00%	1.00%	3.00%
Cost of removal	1.00%	1.00%	2.00%
Other plant-related items	0.00%	0.00%	(1.00%)
Amortization of excess deferred federal income taxes	(6.00%)	(9.00%)	(12.00%)
Renewable energy credits	0.00%	(2.00%)	(2.00%)
Research and development credits	0.00%	0.00%	(1.00%)
Other	0.00%	0.00%	0.00%
Changes in state apportionments, net of federal income taxes	(0.01)	0.06	0
Deferred unamortized ITC recognized on sale of subsidiary	(0.04)	0	0
Effective tax rate	16.00%	24.00%	14.00%
CECONY
STATUTORY TAX RATE
Federal	21.00%	21.00%	21.00%
Changes in computed taxes resulting from:
State income taxes, net of federal income taxes	5.00%	5.00%	5.00%
Taxes attributable to noncontrolling interests	0.00%	0.00%	0.00%
Cost of removal	2.00%	1.00%	1.00%
Other plant-related items	(1.00%)	(1.00%)	(1.00%)
Amortization of excess deferred federal income taxes	(8.00%)	(10.00%)	(11.00%)
Renewable energy credits	0.00%	0.00%	0.00%
Research and development credits	0.00%	0.00%	0.00%
Other	(1.00%)	0.00%	0.00%
Changes in state apportionments, net of federal income taxes	0	0	0
Deferred unamortized ITC recognized on sale of subsidiary	0	0	0
Effective tax rate	18.00%	16.00%	15.00%