Income Tax - Income Tax Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
STATUTORY TAX RATE
Federal	$ 217	$ 190
Federal	21.00%	21.00%
Changes in computed taxes resulting from:
State income tax, net of federal income taxes	$ 55	$ 47
MTA Surcredit amortization, net of federal taxes	13	0
Tax Credits (R&D and renewable energy tax credits)	4	6
Amortization of excess deferred federal income taxes	12	50
Allowance for uncollectible accounts, net of COVID-19 assistance	13	5
Cost of removal	11	11
Other	(1)	3
Effective tax rate	$ 242	$ 184
Changes in computed taxes resulting from:
State income tax, net of federal income taxes	5.40%	5.20%
MTA Surcredit amortization, net of federal taxes	0.013	0
Tax Credits (R&D and renewable energy tax credits)	(0.40%)	(0.70%)
Amortization of excess deferred federal income taxes	(1.10%)	(5.60%)
Allowance for uncollectible accounts, net of COVID-19 assistance	(1.20%)	(0.60%)
Cost of removal	1.00%	1.30%
Other	0.10%	(0.30%)
Effective tax rate	23.50%	20.30%
CECONY
Changes in computed taxes resulting from:
Effective tax rate	$ 227	$ 181
CECONY | Subsidiaries
STATUTORY TAX RATE
Federal	$ 204	$ 184
Federal	21.00%	21.00%
Changes in computed taxes resulting from:
State income tax, net of federal income taxes	$ 51	$ 45
MTA Surcredit amortization, net of federal taxes	12	0
Tax Credits (R&D and renewable energy tax credits)	3	3
Amortization of excess deferred federal income taxes	10	49
Allowance for uncollectible accounts, net of COVID-19 assistance	13	5
Cost of removal	10	11
Other	0	2
Effective tax rate	$ 227	$ 181
Changes in computed taxes resulting from:
State income tax, net of federal income taxes	5.30%	5.20%
MTA Surcredit amortization, net of federal taxes	0.013	0
Tax Credits (R&D and renewable energy tax credits)	(0.30%)	(0.40%)
Amortization of excess deferred federal income taxes	(1.00%)	(5.60%)
Allowance for uncollectible accounts, net of COVID-19 assistance	(1.30%)	(0.60%)
Cost of removal	1.00%	1.20%
Other	0.00%	(0.20%)
Effective tax rate	23.40%	20.60%