Financial Information by Business Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Total revenues	$ 4,060	$ 3,677
Depreciation and amortization	529	497
Operating income/(loss)	799	860
Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	3,517	3,205
Depreciation and amortization	446	415
Operating income/(loss)	711	786
Clean Energy Businesses
Segment Reporting Information [Line Items]
Depreciation and amortization	59	58
Operating income/(loss)	46	28
Con Edison Transmission
Segment Reporting Information [Line Items]
Depreciation and amortization	0	0
Operating income/(loss)	(3)	(3)
CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	446	415
Operating income/(loss)	711	786
CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	332	315
Operating income/(loss)	170	247
CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	90	77
Operating income/(loss)	451	439
CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	24	23
Operating income/(loss)	90	100
O&R | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	24	24
Operating income/(loss)	46	49
O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	17	17
Operating income/(loss)	8	9
O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	7	7
Operating income/(loss)	38	40
Operating segment
Segment Reporting Information [Line Items]
Total revenues	4,060	3,677
Operating segment | Clean Energy Businesses
Segment Reporting Information [Line Items]
Total revenues	260	224
Operating segment | Con Edison Transmission
Segment Reporting Information [Line Items]
Total revenues	1	1
Operating segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	3,517	3,205
Operating segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	2,084	1,968
Operating segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	1,131	973
Operating segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	302	264
Operating segment | O&R | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	285	248
Operating segment | O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	166	145
Operating segment | O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	119	103
Other
Segment Reporting Information [Line Items]
Total revenues	(3)	(1)
Depreciation and amortization	0	0
Operating income/(loss)	(1)	0
Inter-segment | Electric
Segment Reporting Information [Line Items]
Total revenues	0	0
Inter-segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	(25)	(25)
Inter-segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	4	4
Inter-segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	2	2
Inter-segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	$ 19	$ 19