Schedule I - Condensed Financial Information - Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH FLOWS FROM OPERATING ACTIVITIES	$ 3,614	$ 2,156	$ 3,935
INVESTING ACTIVITIES
Proceeds from sale of the Clean Energy Businesses, net of cash and cash equivalents sold	0	3,927	0
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(5,273)	(1,003)	(4,565)
FINANCING ACTIVITIES
Net issuance (payment) of short-term debt	(118)	(202)	1,152
Retirement of long-term debt	(477)	(710)	(406)
Repurchase of common shares	0	(1,000)	0
Issuance of common shares for stock plans	60	56	57
Common stock dividends	(1,100)	(1,096)	(1,089)
NET CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES	1,797	(1,488)	1,014
NET CHANGE FOR THE PERIOD	138	(335)	384
BALANCE AT BEGINNING OF PERIOD	1,195	1,530	1,146
BALANCE AT END OF PERIOD	1,333	1,195	1,530
CECONY
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH FLOWS FROM OPERATING ACTIVITIES	3,358	2,285	3,263
INVESTING ACTIVITIES
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(4,923)	(4,439)	(3,926)
FINANCING ACTIVITIES
Net issuance (payment) of short-term debt	(209)	(397)	939
Issuance of term loan	500	0	0
Retirement of long-term debt	(475)	0	0
NET CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES	1,681	2,236	799
NET CHANGE FOR THE PERIOD	116	82	136
BALANCE AT BEGINNING OF PERIOD	1,138	1,056	920
BALANCE AT END OF PERIOD	1,254	1,138	1,056
Parent Company
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH FLOWS FROM OPERATING ACTIVITIES	1,204	772	1,015
INVESTING ACTIVITIES
Contributions to subsidiaries	(175)	(1,854)	(150)
Proceeds from sale of the Clean Energy Businesses, net of cash and cash equivalents sold	0	3,927	0
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(175)	2,073	(150)
FINANCING ACTIVITIES
Net issuance (payment) of short-term debt	9	57	232
Issuance of term loan	0	200	400
Retirement of term loan	0	(600)	0
Retirement of long-term debt	0	(650)	(293)
Repurchase of common shares	0	(1,000)	0
Issuance of common shares for stock plans	60	56	57
Common stock dividends	(1,100)	(1,096)	(1,089)
NET CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES	(1,031)	(3,033)	(693)
NET CHANGE FOR THE PERIOD	(2)	(188)	172
BALANCE AT BEGINNING OF PERIOD	3	191	19
BALANCE AT END OF PERIOD	$ 1	$ 3	$ 191