Financial Information by Business Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Total revenues	$ 3,872	$ 4,165	$ 11,219	$ 11,639
Depreciation and amortization	512	525	1,506	1,593
Operating income/(loss)	722	889	2,745	2,074
CECONY
Segment Reporting Information [Line Items]
Total revenues	3,590	3,549	10,287	9,972
Depreciation and amortization	485	441	1,428	1,341
Operating income/(loss)	679	738	1,750	1,729
CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	485	441	1,428	1,341
Operating income/(loss)	679	738	1,750	1,729
CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	352	324	1,035	994
Operating income/(loss)	867	843	1,292	1,233
CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	108	93	319	275
Operating income/(loss)	(108)	(40)	533	511
CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	25	24	74	72
Operating income/(loss)	(80)	(65)	(75)	(15)
O&R | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	26	25	78	73
Operating income/(loss)	48	51	100	110
O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	19	18	56	53
Operating income/(loss)	59	61	73	85
O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	7	7	22	20
Operating income/(loss)	(11)	(10)	27	25
Operating segment
Segment Reporting Information [Line Items]
Total revenues	3,872	4,165	11,219	11,639
Operating segment | Clean Energy Businesses
Segment Reporting Information [Line Items]
Total revenues	0	325	129	857
Depreciation and amortization	0	60	0	178
Operating income/(loss)	0	104	37	248
Operating segment | Con Edison Transmission
Segment Reporting Information [Line Items]
Total revenues	1	1	3	3
Depreciation and amortization	1	0	1	1
Operating income/(loss)	(2)	(2)	(6)	(8)
Operating segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	3,590	3,549	10,287	9,972
Operating segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	3,223	3,077	7,722	7,401
Operating segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	318	414	2,140	2,127
Operating segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	49	58	425	444
Operating segment | O&R | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	281	291	803	813
Operating segment | O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	246	252	588	594
Operating segment | O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	35	39	215	219
Inter-segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	(25)	(26)	(75)	(77)
Inter-segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	4	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	19	55	57
Other
Segment Reporting Information [Line Items]
Total revenues	0	(1)	(3)	(6)
Depreciation and amortization	0	(1)	(1)	0
Operating income/(loss)	$ (3)	$ (2)	$ 864	$ (5)