Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 4,225	$ 3,853	$ 11,777	$ 10,850
Total revenues	4,092	3,872	11,587	11,219
Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	(133)	19	(190)	369
CECONY
Disaggregation of Revenue [Line Items]
Total revenues	3,762	3,590	10,730	10,287
Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues	4,092	3,872	11,587	11,219
Operating Segments | Clean Energy Businesses
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers			0	82
Total revenues			0	129
Operating Segments | Clean Energy Businesses | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues			0	47
Operating Segments | Clean Energy Businesses | Renewables
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers			0	68
Total revenues			0	68
Operating Segments | Clean Energy Businesses | Renewables | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues			0	0
Operating Segments | Clean Energy Businesses | Energy services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers			0	7
Total revenues			0	7
Operating Segments | Clean Energy Businesses | Energy services | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues			0	0
Operating Segments | Clean Energy Businesses | Develop/Transfer Projects
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers			0	7
Total revenues			0	7
Operating Segments | Clean Energy Businesses | Develop/Transfer Projects | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues			0	0
Operating Segments | Clean Energy Businesses | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers			0	0
Total revenues			0	47
Operating Segments | Clean Energy Businesses | Other | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues			0	47
Operating Segments | Con Edison Transmission
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1	1	3	3
Total revenues	1	1	3	3
Operating Segments | Con Edison Transmission | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | CECONY | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,909	3,579	10,913	9,980
Total revenues	3,762	3,590	10,730	10,287
Operating Segments | CECONY | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(147)	11	(183)	307
Operating Segments | CECONY | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,493	3,195	8,300	7,449
Total revenues	3,376	3,223	8,188	7,722
Operating Segments | CECONY | Electric | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(117)	28	(112)	273
Operating Segments | CECONY | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	364	338	2,177	2,117
Total revenues	337	318	2,119	2,140
Operating Segments | CECONY | Gas | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(27)	(20)	(58)	23
Operating Segments | CECONY | Steam | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	52	46	436	414
Total revenues	49	49	423	425
Operating Segments | CECONY | Steam | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(3)	3	(13)	11
Operating Segments | O&R | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	315	273	861	785
Total revenues	329	281	855	803
Operating Segments | O&R | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	14	8	(6)	18
Operating Segments | O&R | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	309	242	688	574
Total revenues	293	246	662	588
Operating Segments | O&R | Electric | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(16)	4	(26)	14
Operating Segments | O&R | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	6	31	173	211
Total revenues	36	35	193	215
Operating Segments | O&R | Gas | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	30	4	20	4
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Total revenues	0	0	(1)	(3)
Other | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ 0	$ (1)	$ (3)