Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 2,773	$ 3,381	$ 6,996	$ 7,341
Total revenues	2,944	3,415	7,347	7,475
Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	2,744	2,906	6,697	6,423
Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	171	34	351	134
Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues	2,944	3,415	7,347	7,475
Operating Segments | Clean Energy Businesses
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	232	82	390
Total revenues	0	272	129	532
Operating Segments | Clean Energy Businesses | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	0	40	47	142
Operating Segments | Clean Energy Businesses | Renewables
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	199	68	327
Total revenues	0	199	68	327
Operating Segments | Clean Energy Businesses | Renewables | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Clean Energy Businesses | Energy services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	25	7	44
Total revenues	0	25	7	44
Operating Segments | Clean Energy Businesses | Energy services | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Clean Energy Businesses | Develop/Transfer Projects
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	8	7	19
Total revenues	0	8	7	19
Operating Segments | Clean Energy Businesses | Develop/Transfer Projects | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | Clean Energy Businesses | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Total revenues	0	40	47	142
Operating Segments | Clean Energy Businesses | Other | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	0	40	47	142
Operating Segments | Con Edison Transmission
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1	1	2	2
Total revenues	1	1	2	2
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	2,577	2,908	6,401	6,422
Total revenues	2,744	2,906	6,697	6,423
Operating Segments | CECONY | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	167	(2)	296	1
Operating Segments | CECONY | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,991	2,255	4,254	4,360
Total revenues	2,144	2,240	4,500	4,324
Operating Segments | CECONY | Electric | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	153	(15)	246	(36)
Operating Segments | CECONY | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	521	571	1,779	1,681
Total revenues	531	582	1,822	1,713
Operating Segments | CECONY | Gas | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	10	11	43	32
Operating Segments | CECONY | Steam | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	65	82	368	381
Total revenues	69	84	375	386
Operating Segments | CECONY | Steam | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	4	2	7	5
Operating Segments | O&R | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	195	240	511	527
Total revenues	200	238	521	522
Operating Segments | O&R | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	5	(2)	10	(5)
Operating Segments | O&R | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	154	175	332	339
Total revenues	159	177	341	342
Operating Segments | O&R | Electric | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	5	2	9	3
Operating Segments | O&R | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	41	65	179	188
Total revenues	41	61	180	180
Operating Segments | O&R | Gas | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	0	(4)	1	(8)
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Total revenues	(1)	(2)	(2)	(4)
Other | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ (1)	$ (2)	$ (2)	$ (4)