Financial Information by Business Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Total revenues	$ 3,415	$ 2,971	$ 7,475	$ 6,648
Depreciation and amortization	539	502	1,068	1,000
Operating income/(loss)	387	418	1,185	1,279
Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	2,906	2,486	6,423	5,692
Depreciation and amortization	455	423	900	838
Operating income/(loss)	280	321	991	1,108
Clean Energy Businesses
Segment Reporting Information [Line Items]
Depreciation and amortization	59	55	119	114
Operating income/(loss)	97	89	143	117
Con Edison Transmission
Segment Reporting Information [Line Items]
Depreciation and amortization	0	0	0	1
Operating income/(loss)	(2)	(1)	(5)	(4)
CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	455	423	900	838
Operating income/(loss)	280	321	991	1,108
CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	338	320	670	635
Operating income/(loss)	220	255	390	501
CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	93	80	183	157
Operating income/(loss)	100	99	550	538
CECONY | Steam
Segment Reporting Information [Line Items]
Operating income/(loss)			51
CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	24	23	47	46
Operating income/(loss)	(40)	(33)		69
O&R | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	25	24	48	47
Operating income/(loss)	14	11	59	61
O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	18	17	35	34
Operating income/(loss)	16	14	23	22
O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	7	7	13	13
Operating income/(loss)	(2)	(3)	36	39
Operating segment
Segment Reporting Information [Line Items]
Total revenues	3,415	2,971	7,475	6,648
Operating segment | Clean Energy Businesses
Segment Reporting Information [Line Items]
Total revenues	272	291	532	515
Operating segment | Con Edison Transmission
Segment Reporting Information [Line Items]
Total revenues	1	1	2	2
Operating segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	2,906	2,486	6,423	5,692
Operating segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	2,240	1,963	4,324	3,931
Operating segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	582	449	1,713	1,423
Operating segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	84	74	386	338
Operating segment | O&R | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	238	194	522	442
Operating segment | O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	177	153	342	299
Operating segment | O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	61	41	180	143
Other
Segment Reporting Information [Line Items]
Total revenues	(2)	(1)	(4)	(3)
Depreciation and amortization	0	0	1	0
Operating income/(loss)	(2)	(2)	(3)	(3)
Inter-segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	(25)	(25)	(50)	(50)
Inter-segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	5	5	9	9
Inter-segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	2	2	4	4
Inter-segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	$ 18	$ 18	$ 37	$ 37