Financial Information by Business Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Total revenues	$ 3,220	$ 2,944	$ 7,495	$ 7,347
Depreciation and amortization	512	496	1,051	994
Operating income (loss)	320	284	1,331	2,022
CECONY
Segment Reporting Information [Line Items]
Total revenues	2,996	2,744	6,967	6,697
Depreciation and amortization	482	470	993	943
Operating income (loss)	314	262	1,304	1,071
CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	482	470	993	943
Operating income (loss)	314	262	1,304	1,071
CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	345	339	715	683
Operating income (loss)	272	232	512	424
CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	112	106	226	211
Operating income (loss)	85	83	701	642
CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	25	25	52	49
Operating income (loss)	(43)	(53)	91	5
O&R | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	29	26	58	51
Operating income (loss)	9	11	64	52
O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	20	18	40	36
Operating income (loss)	12	13	25	14
O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	9	8	18	15
Operating income (loss)	(3)	(2)	39	38
Operating segment
Segment Reporting Information [Line Items]
Total revenues	3,220	2,944	7,495	7,347
Operating segment | Clean Energy Businesses
Segment Reporting Information [Line Items]
Total revenues			0	129
Depreciation and amortization			0	0
Operating income (loss)			0	37
Operating segment | Con Edison Transmission
Segment Reporting Information [Line Items]
Total revenues	1	1	2	2
Depreciation and amortization	0	0	1	0
Operating income (loss)	(2)	(2)	(5)	(4)
Operating segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	2,996	2,744	6,967	6,697
Operating segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	2,370	2,144	4,812	4,500
Operating segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	538	531	1,781	1,822
Operating segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	88	69	374	375
Operating segment | O&R | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	224	200	527	521
Operating segment | O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	180	159	370	341
Operating segment | O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	44	41	157	180
Inter-segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	(26)	(25)	(52)	(50)
Inter-segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	5	5	10	9
Inter-segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	3	2	5	4
Inter-segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	18	18	37	37
Other
Segment Reporting Information [Line Items]
Total revenues	(1)	(1)	(1)	(2)
Depreciation and amortization	1	0	(1)	0
Operating income (loss)	$ (1)	$ 13	$ (32)	$ 866