Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 14,476	$ 15,455	$ 13,456
Cost of services provided	14,663	15,670	13,676
Other
Disaggregation of Revenue [Line Items]
Cost of services provided	187	215	220
CECONY
Disaggregation of Revenue [Line Items]
Cost of services provided	13,476	13,268	11,716
Operating Segments | Clean Energy Businesses
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	82	998	917
Cost of services provided	129	1,319	1,022
Operating Segments | Clean Energy Businesses | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	47	321	105
Operating Segments | Clean Energy Businesses | Renewables
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	68	637	638
Cost of services provided	68	637	638
Operating Segments | Clean Energy Businesses | Renewables | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	0	0	0
Operating Segments | Clean Energy Businesses | Energy services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	7	317	234
Cost of services provided	7	317	234
Operating Segments | Clean Energy Businesses | Energy services | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	0	0	0
Operating Segments | Clean Energy Businesses | Develop/Transfer Projects
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	7	44	45
Cost of services provided	7	44	45
Operating Segments | Clean Energy Businesses | Develop/Transfer Projects | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	0	0	0
Operating Segments | Clean Energy Businesses | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0
Cost of services provided	47	321	105
Operating Segments | Clean Energy Businesses | Other | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	47	321	105
Operating Segments | Con Edison Transmission
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	4	4	4
Cost of services provided	4	4	4
Operating Segments | Con Edison Transmission | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	0	0	0
Operating Segments | CECONY
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	13,364	13,376	11,579
Cost of services provided	13,476	13,268	11,716
Operating Segments | CECONY | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	112	(108)	137
Operating Segments | CECONY | Decoupling Mechanism
Disaggregation of Revenue [Line Items]
Cost of services provided			48
Operating Segments | CECONY | Net EAMs
Disaggregation of Revenue [Line Items]
Cost of services provided			34
Operating Segments | CECONY | LPCs
Disaggregation of Revenue [Line Items]
Cost of services provided			74
Operating Segments | CECONY | Electric
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	9,946	9,917	8,736
Cost of services provided	10,078	9,751	8,806
Operating Segments | CECONY | Electric | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	132	(166)	70
Operating Segments | CECONY | Gas
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,867	2,875	2,324
Cost of services provided	2,829	2,924	2,378
Operating Segments | CECONY | Gas | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	(38)	49	54
Operating Segments | CECONY | Steam
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	551	584	519
Cost of services provided	569	593	532
Operating Segments | CECONY | Steam | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	18	9	13
Operating Segments | O&R
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,026	1,077	956
Cost of services provided	1,056	1,085	941
Operating Segments | O&R | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	30	8	(15)
Operating Segments | O&R | Decoupling Mechanism
Disaggregation of Revenue [Line Items]
Cost of services provided			(18)
Operating Segments | O&R | Net EAMs
Disaggregation of Revenue [Line Items]
Cost of services provided			2
Operating Segments | O&R | LPCs
Disaggregation of Revenue [Line Items]
Cost of services provided			4
Operating Segments | O&R | Electric
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	740	771	691
Cost of services provided	759	773	681
Operating Segments | O&R | Electric | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	19	2	(10)
Operating Segments | O&R | Gas
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	286	306	265
Cost of services provided	297	312	260
Operating Segments | O&R | Gas | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	11	6	(5)
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0
Cost of services provided	(2)	(6)	(7)
Other | Other
Disaggregation of Revenue [Line Items]
Cost of services provided	$ (2)	$ (6)	$ (7)