Financial Information by Business Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Total revenues	$ 4,092	$ 3,872	$ 11,587	$ 11,219
Depreciation and amortization	550	512	1,601	1,506
Operating income (loss)	862	722	2,193	2,745
CECONY
Segment Reporting Information [Line Items]
Total revenues	3,762	3,590	10,730	10,287
Depreciation and amortization	520	485	1,512	1,428
Operating income (loss)	803	679	2,107	1,750
CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	520	485	1,512	1,428
Operating income (loss)	803	679	2,107	1,750
CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	376	352	1,090	1,035
Operating income (loss)	998	867	1,511	1,292
CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	117	108	343	319
Operating income (loss)	(112)	(108)	588	533
CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	27	25	79	74
Operating income (loss)	(83)	(80)	8	(75)
O&R | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	30	26	87	78
Operating income (loss)	63	48	127	100
O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	21	19	61	56
Operating income (loss)	72	59	97	73
O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	9	7	26	22
Operating income (loss)	(9)	(11)	30	27
Operating segment
Segment Reporting Information [Line Items]
Total revenues	4,092	3,872	11,587	11,219
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	3	3
Depreciation and amortization	0	1	1	1
Operating income (loss)	(1)	(2)	(6)	(6)
Operating segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	3,762	3,590	10,730	10,287
Operating segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	3,376	3,223	8,188	7,722
Operating segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	337	318	2,119	2,140
Operating segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	49	49	423	425
Operating segment | O&R | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	329	281	855	803
Operating segment | O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	293	246	662	588
Operating segment | O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	36	35	193	215
Inter-segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	(26)	(25)	(78)	(75)
Inter-segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	5	4	15	14
Inter-segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	2	2	7	6
Inter-segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	19	19	56	55
Other
Segment Reporting Information [Line Items]
Total revenues	0	0	(1)	(3)
Depreciation and amortization	0	0	1	(1)
Operating income (loss)	$ (3)	$ (3)	$ (35)	$ 864