Financial Information by Business Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Total revenues	$ 4,165	$ 3,613	$ 11,639	$ 10,261
Depreciation and amortization	525	512	1,593	1,511
Operating income/(loss)	889	850	2,074	2,129
Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	3,549	3,092	9,972	8,784
Depreciation and amortization	441	429	1,341	1,267
Operating income/(loss)	738	728	1,729	1,836
Clean Energy Businesses
Segment Reporting Information [Line Items]
Depreciation and amortization	60	58	178	172
Operating income/(loss)	104	79	248	196
Con Edison Transmission
Segment Reporting Information [Line Items]
Depreciation and amortization	0	0	1	1
Operating income/(loss)	(2)	(2)	(8)	(7)
CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	441	429	1,341	1,267
Operating income/(loss)	738	728	1,729	1,836
CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	324	324	994	959
Operating income/(loss)	843	834	1,233	1,337
CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	93	82	275	239
Operating income/(loss)	(40)	(48)	511	490
CECONY | Steam
Segment Reporting Information [Line Items]
Operating income/(loss)			(15)
CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	24	23	72	69
Operating income/(loss)	(65)	(58)		9
O&R | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	25	24	73	71
Operating income/(loss)	51	47	110	108
O&R | Electric
Segment Reporting Information [Line Items]
Operating income/(loss)			85
O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	18	18	53	52
Operating income/(loss)	61	55	85	78
O&R | Gas
Segment Reporting Information [Line Items]
Operating income/(loss)			25
O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	7	6	20	19
Operating income/(loss)	(10)	(8)	25	30
Operating segment
Segment Reporting Information [Line Items]
Total revenues	4,165	3,613	11,639	10,261
Operating segment | Clean Energy Businesses
Segment Reporting Information [Line Items]
Total revenues	325	264	857	779
Operating segment | Con Edison Transmission
Segment Reporting Information [Line Items]
Total revenues	1	1	3	3
Operating segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	3,549	3,092	9,972	8,784
Operating segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	3,077	2,730	7,401	6,661
Operating segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	414	307	2,127	1,730
Operating segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	58	55	444	393
Operating segment | O&R | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	291	257	813	699
Operating segment | O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	252	223	594	522
Operating segment | O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	39	34	219	177
Other
Segment Reporting Information [Line Items]
Total revenues	(1)	(1)	(6)	(4)
Depreciation and amortization	(1)	1	0	0
Operating income/(loss)	(2)	(2)	(5)	(4)
Inter-segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	(26)	(25)	(77)	(75)
Inter-segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	5	5	14	14
Inter-segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	2	2	6	6
Inter-segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	$ 19	$ 18	$ 57	$ 55