Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 4,222	$ 3,953
Total revenues	4,403	4,060
Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	3,953	3,517
Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	181	107
Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues	4,403	4,060
Operating Segments | Clean Energy Businesses
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	82	159
Total revenues	129	260
Operating Segments | Clean Energy Businesses | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	47	101
Operating Segments | Clean Energy Businesses | Renewables
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	68	129
Total revenues	68	129
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	7	19
Total revenues	7	19
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	7	11
Total revenues	7	11
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	47	101
Operating Segments | Clean Energy Businesses | Other | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	47	101
Operating Segments | Con Edison Transmission
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1	1
Total revenues	1	1
Operating Segments | Con Edison Transmission | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	0	0
Operating Segments | CECONY | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,823	3,510
Total revenues	3,953	3,517
Operating Segments | CECONY | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	130	7
Operating Segments | CECONY | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,263	2,107
Total revenues	2,356	2,084
Operating Segments | CECONY | Electric | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	93	(23)
Operating Segments | CECONY | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,257	1,104
Total revenues	1,291	1,131
Operating Segments | CECONY | Gas | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	34	27
Operating Segments | CECONY | Steam | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	303	299
Total revenues	306	302
Operating Segments | CECONY | Steam | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	3	3
Operating Segments | O&R | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	316	283
Total revenues	321	285
Operating Segments | O&R | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	5	2
Operating Segments | O&R | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	178	163
Total revenues	182	166
Operating Segments | O&R | Electric | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	4	3
Operating Segments | O&R | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	138	120
Total revenues	139	119
Operating Segments | O&R | Gas | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	1	(1)
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Total revenues	(1)	(3)
Other | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ (1)	$ (3)