Schedule I - Condensed Financial Information - Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH FLOWS FROM OPERATING ACTIVITIES	$ 2,156	$ 3,935	$ 2,733
INVESTING ACTIVITIES
Proceeds from sale of the Clean Energy Businesses, net of cash and cash equivalents sold	3,927	0	629
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(1,003)	(4,565)	(3,484)
FINANCING ACTIVITIES
Net (payment)/issuance of short-term debt	(752)	1,702	(382)
Retirement of long-term debt	(710)	(406)	(1,960)
Debt issuance costs	(32)	(13)	(40)
Repurchase of common shares	(1,000)	0	0
Issuance of common shares for stock plans	56	57	60
Issuance of common shares - public offering	0	0	775
Common stock dividends	(1,096)	(1,089)	(1,030)
NET CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES	(1,488)	1,014	461
NET CHANGE FOR THE PERIOD	(335)	384	(290)
BALANCE AT BEGINNING OF PERIOD	1,530	1,146	1,436
BALANCE AT END OF PERIOD	1,195	1,530	1,146
CECONY
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH FLOWS FROM OPERATING ACTIVITIES	2,285	3,263	2,186
INVESTING ACTIVITIES
NET CASH FLOWS USED IN INVESTING ACTIVITIES	(4,439)	(3,926)	(3,729)
FINANCING ACTIVITIES
Net (payment)/issuance of short-term debt	(397)	939	(299)
Retirement of long-term debt	0	0	(640)
Debt issuance costs	(31)	(12)	(27)
NET CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES	2,236	799	1,396
NET CHANGE FOR THE PERIOD	82	136	(147)
BALANCE AT BEGINNING OF PERIOD	1,056	920	1,067
BALANCE AT END OF PERIOD	1,138	1,056	920
Parent Company
Condensed Cash Flow Statements, Captions [Line Items]
NET CASH FLOWS FROM OPERATING ACTIVITIES	772	1,015	1,459
INVESTING ACTIVITIES
Contributions to subsidiaries	(1,854)	(150)	(1,135)
Debt receivable from affiliated companies	0	0	875
Proceeds from sale of the Clean Energy Businesses, net of cash and cash equivalents sold	3,927	0	0
NET CASH FLOWS USED IN INVESTING ACTIVITIES	2,073	(150)	(260)
FINANCING ACTIVITIES
Net (payment)/issuance of short-term debt	(343)	632	50
Retirement of long-term debt	(650)	(293)	(1,178)
Debt issuance costs	0	0	(1)
Repurchase of common shares	(1,000)	0	0
Issuance of common shares for stock plans	56	57	60
Issuance of common shares - public offering	0	0	775
Common stock dividends	(1,096)	(1,089)	(1,030)
NET CASH FLOWS FROM (USED IN) FINANCING ACTIVITIES	(3,033)	(693)	(1,324)
NET CHANGE FOR THE PERIOD	(188)	172	(125)
BALANCE AT BEGINNING OF PERIOD	191	19	144
BALANCE AT END OF PERIOD	$ 3	$ 191	$ 19