Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 4,162	$ 3,659	$ 11,503	$ 10,212
Total revenues	4,165	3,613	11,639	10,261
Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	3,549	3,092	9,972	8,784
Other
Disaggregation of Revenue [Line Items]
Total revenues	3	(46)	136	49
Operating Segments
Disaggregation of Revenue [Line Items]
Total revenues	4,165	3,613	11,639	10,261
Operating Segments | Clean Energy Businesses
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	247	264	637	713
Total revenues	325	264	857	779
Operating Segments | Clean Energy Businesses | Other
Disaggregation of Revenue [Line Items]
Total revenues	78	0	220	66
Operating Segments | Clean Energy Businesses | Renewables
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	197	185	524	519
Total revenues	197	185	524	519
Operating Segments | Clean Energy Businesses | Renewables | Other
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	13	65	57	168
Total revenues	13	65	57	168
Operating Segments | Clean Energy Businesses | Energy services | Other
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	37	14	56	26
Total revenues	37	14	56	26
Operating Segments | Clean Energy Businesses | Develop/Transfer Projects | Other
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	78	0	220	66
Operating Segments | Clean Energy Businesses | Other | Other
Disaggregation of Revenue [Line Items]
Total revenues	78	0	220	66
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
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	3,629	3,133	10,051	8,777
Total revenues	3,549	3,092	9,972	8,784
Operating Segments | CECONY | Other | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(80)	(41)	(79)	7
Operating Segments | CECONY | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,165	2,776	7,525	6,695
Total revenues	3,077	2,730	7,401	6,661
Operating Segments | CECONY | Electric | Other | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(88)	(46)	(124)	(34)
Operating Segments | CECONY | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	409	305	2,090	1,699
Total revenues	414	307	2,127	1,730
Operating Segments | CECONY | Gas | Other | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	5	2	37	31
Operating Segments | CECONY | Steam | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	55	52	436	383
Total revenues	58	55	444	393
Operating Segments | CECONY | Steam | Other | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	3	3	8	10
Operating Segments | O&R | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	285	261	812	719
Total revenues	291	257	813	699
Operating Segments | O&R | Other | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	6	(4)	1	(20)
Operating Segments | O&R | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	256	229	595	535
Total revenues	252	223	594	522
Operating Segments | O&R | Electric | Other | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(4)	(6)	(1)	(13)
Operating Segments | O&R | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	29	32	217	184
Total revenues	39	34	219	177
Operating Segments | O&R | Gas | Other | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	10	2	2	(7)
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Total revenues	(1)	(1)	(6)	(4)
Other | Other
Disaggregation of Revenue [Line Items]
Total revenues	$ (1)	$ (1)	$ (6)	$ (4)