Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 13,456	$ 12,026	$ 12,144
Revenues	13,676	12,246	12,574
Other
Disaggregation of Revenue [Line Items]
Revenues	220	220	430
CECONY
Disaggregation of Revenue [Line Items]
Revenues	11,716	10,647	10,821
CECONY | Decoupling Mechanisms
Disaggregation of Revenue [Line Items]
Revenues	48
CECONY | EAMs
Disaggregation of Revenue [Line Items]
Revenues	34
CECONY | LPCs
Disaggregation of Revenue [Line Items]
Revenues	74
O&R | Decoupling Mechanisms
Disaggregation of Revenue [Line Items]
Revenues	(18)
O&R | EAMs
Disaggregation of Revenue [Line Items]
Revenues	2
O&R | LPCs
Disaggregation of Revenue [Line Items]
Revenues	4
Operating Segments | Clean Energy Businesses
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	917	661	646
Revenues	1,022	736	857
Operating Segments | Clean Energy Businesses | Other
Disaggregation of Revenue [Line Items]
Revenues	105	75	211
Operating Segments | Clean Energy Businesses | Renewables
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	683	609	575
Revenues	683	609	575
Operating Segments | Clean Energy Businesses | Renewables | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Operating Segments | Clean Energy Businesses | Energy services
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	234	52	71
Revenues	234	52	71
Operating Segments | Clean Energy Businesses | Energy services | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Operating Segments | Clean Energy Businesses | Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0
Revenues	105	75	211
Operating Segments | Clean Energy Businesses | Other | Other
Disaggregation of Revenue [Line Items]
Revenues	105	75	211
Operating Segments | Con Edison Transmission
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	4	4	4
Revenues	4	4	4
Operating Segments | Con Edison Transmission | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	0
Operating Segments | CECONY
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	11,579	10,518	10,620
Revenues	11,716	10,647	10,821
Operating Segments | CECONY | Other
Disaggregation of Revenue [Line Items]
Revenues	137	129	201
Operating Segments | CECONY | Electric
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	8,736	8,026	7,913
Revenues	8,806	8,103	8,062
Operating Segments | CECONY | Electric | Other
Disaggregation of Revenue [Line Items]
Revenues	70	77	149
Operating Segments | CECONY | Gas
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,324	1,998	2,097
Revenues	2,378	2,036	2,132
Operating Segments | CECONY | Gas | Other
Disaggregation of Revenue [Line Items]
Revenues	54	38	35
Operating Segments | CECONY | Steam
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	519	494	610
Revenues	532	508	627
Operating Segments | CECONY | Steam | Other
Disaggregation of Revenue [Line Items]
Revenues	13	14	17
Operating Segments | O&R
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	956	843	874
Revenues	941	862	893
Operating Segments | O&R | Other
Disaggregation of Revenue [Line Items]
Revenues	(15)	19	19
Operating Segments | O&R | Electric
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	691	619	627
Revenues	681	629	634
Operating Segments | O&R | Electric | Other
Disaggregation of Revenue [Line Items]
Revenues	(10)	10	7
Operating Segments | O&R | Gas
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	265	224	247
Revenues	260	233	259
Operating Segments | O&R | Gas | Other
Disaggregation of Revenue [Line Items]
Revenues	(5)	9	12
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0
Revenues	(7)	(3)	(1)
Other | Other
Disaggregation of Revenue [Line Items]
Revenues	(7)	(3)	(1)
Other | O&R
Disaggregation of Revenue [Line Items]
Revenues	$ 0	$ 0	$ 0