Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 4,568	$ 4,225	$ 13,085	$ 11,777
Total revenues	4,530	4,092	12,924	11,587
Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	(38)	(133)	(161)	(190)
CECONY
Disaggregation of Revenue [Line Items]
Total revenues	4,181	3,762	11,963	10,730
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
Disaggregation of Revenue [Line Items]
Total revenues	4,181	3,762	11,963	10,730
Operating Segments | CECONY | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	4,200	3,909	12,091	10,913
Total revenues	4,181	3,762	11,963	10,730
Operating Segments | CECONY | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(19)	(147)	(128)	(183)
Operating Segments | CECONY | Electric
Disaggregation of Revenue [Line Items]
Total revenues	3,733	3,376	9,000	8,188
Operating Segments | CECONY | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,722	3,493	9,055	8,300
Total revenues		3,376		8,188
Operating Segments | CECONY | Electric | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	11	(117)	(55)	(112)
Operating Segments | CECONY | Gas
Disaggregation of Revenue [Line Items]
Total revenues	392	337	2,446	2,119
Operating Segments | CECONY | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	421	364	2,515	2,177
Total revenues		337		2,119
Operating Segments | CECONY | Gas | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(29)	(27)	(69)	(58)
Operating Segments | CECONY | Steam
Disaggregation of Revenue [Line Items]
Total revenues	56	49	517	423
Operating Segments | CECONY | Steam | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	57	52	521	436
Total revenues		49		423
Operating Segments | CECONY | Steam | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(1)	(3)	(4)	(13)
Operating Segments | O&R
Disaggregation of Revenue [Line Items]
Total revenues	349	329	959	855
Operating Segments | O&R | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	367	315	991	861
Total revenues	349	329	959	855
Operating Segments | O&R | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(18)	14	(32)	(6)
Operating Segments | O&R | Electric
Disaggregation of Revenue [Line Items]
Total revenues	308	293	719	662
Operating Segments | O&R | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	325	309	739	688
Total revenues		293		662
Operating Segments | O&R | Electric | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(17)	(16)	(20)	(26)
Operating Segments | O&R | Gas
Disaggregation of Revenue [Line Items]
Total revenues	41	36	240	193
Operating Segments | O&R | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	42	6	252	173
Total revenues		36		193
Operating Segments | O&R | Gas | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(1)	30	(12)	20
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Total revenues	(1)	0	(1)	(1)
Other | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ (1)	$ 0	$ (1)	$ (1)