Income Tax - Income Tax Reconciliation (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
STATUTORY TAX RATE
Federal	21.00%	21.00%	21.00%	21.00%
Changes in computed taxes resulting from:
State income tax, net of federal income tax benefit	8.00%	6.00%	5.00%	6.00%
Taxes attributable to non-controlling interest			0.00%	1.00%
Cost of removal	1.00%	1.00%	1.00%	1.00%
Other plant-related items			0.00%	0.00%
Renewable energy credits	0.00%	(1.00%)	(1.00%)	(2.00%)
Allowance for uncollectible accounts, net of COVID-19 assistance	(2.00%)	0.00%
Amortization of excess deferred federal income taxes	(6.00%)	(6.00%)	(5.00%)	(8.00%)
State taxes on sale of subsidiary, net of federal income tax benefit	0.01	0
Changes in state apportionments, net of federal income taxes			(0.01)	0
Deferred unamortized investment tax credit recognized on sale of subsidiary			(0.04)	0
Other	(2.00%)	0.00%	0.00%	0.00%
Effective tax rate	21.00%	21.00%	16.00%	19.00%
CECONY | Subsidiaries
STATUTORY TAX RATE
Federal	21.00%	21.00%	21.00%	21.00%
Changes in computed taxes resulting from:
State income tax, net of federal income tax benefit	5.00%	5.00%	5.00%	5.00%
Taxes attributable to non-controlling interest			0.00%	0.00%
Cost of removal	1.00%	1.00%	2.00%	2.00%
Other plant-related items			(1.00%)	(1.00%)
Renewable energy credits	0.00%	0.00%	0.00%	0.00%
Allowance for uncollectible accounts, net of COVID-19 assistance	(2.00%)	1.00%
Amortization of excess deferred federal income taxes	(7.00%)	(7.00%)	(8.00%)	(10.00%)
State taxes on sale of subsidiary, net of federal income tax benefit	0	0
Changes in state apportionments, net of federal income taxes			0	0
Deferred unamortized investment tax credit recognized on sale of subsidiary			0	0
Other	(1.00%)	(1.00%)	0.00%	0.00%
Effective tax rate	17.00%	20.00%	19.00%	17.00%