Financial Information by Business Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Total revenues	$ 4,280	$ 4,403
Depreciation and amortization	539	499
Operating income/(loss)	1,011	1,739
CECONY
Segment Reporting Information [Line Items]
Total revenues	3,971	3,953
Depreciation and amortization	510	473
Operating income/(loss)	989	809
CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	510	473
Operating income/(loss)	989	809
CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	370	343
Operating income/(loss)	240	194
CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	114	105
Operating income/(loss)	615	559
CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	26	25
Operating income/(loss)	134	56
O&R | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	29	25
Operating income/(loss)	56	41
O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	20	18
Operating income/(loss)	14	1
O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Depreciation and amortization	9	7
Operating income/(loss)	42	40
Operating segment
Segment Reporting Information [Line Items]
Total revenues	4,280	4,403
Operating segment | Clean Energy Businesses
Segment Reporting Information [Line Items]
Total revenues	0	129
Depreciation and amortization	0	0
Operating income/(loss)	0	36
Operating segment | Con Edison Transmission
Segment Reporting Information [Line Items]
Total revenues	1	1
Depreciation and amortization	0	0
Operating income/(loss)	(3)	(2)
Operating segment | CECONY | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	3,971	3,953
Operating segment | CECONY | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	2,441	2,356
Operating segment | CECONY | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	1,243	1,291
Operating segment | CECONY | Steam | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	287	306
Operating segment | O&R | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	308	321
Operating segment | O&R | Electric | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	195	182
Operating segment | O&R | Gas | Subsidiaries
Segment Reporting Information [Line Items]
Total revenues	113	139
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	5
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	18
Other
Segment Reporting Information [Line Items]
Total revenues	0	(1)
Depreciation and amortization	0	1
Operating income/(loss)	$ (31)	$ 855