Financial Information by Business Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	$ 13,676	$ 12,246	$ 12,574
Depreciation and amortization	2,032	1,920	1,684
Operating income	2,826	2,654	2,676
Other Income (deductions)	(538)	(401)	51
Interest charges	905	1,019	991
Income taxes on operating income	340	193	300
Total assets	63,116	62,895	58,079
Capital expenditures	3,964	4,085	3,676
Income tax expense (benefit) on non-operating income	(150)	(103)	(4)
Parent Company
Segment Reporting Information [Line Items]
Total assets	21,620	21,499
CECONY
Segment Reporting Information [Line Items]
Revenues	11,716	10,647	10,821
Depreciation and amortization	1,705	1,598	1,373
Operating income	2,460	2,310	2,348
Other Income (deductions)	(108)	(171)	(35)
Total assets	52,655	50,967
Income tax expense (benefit) on non-operating income	(6)	(3)	(7)
Operating segment | Clean Energy Businesses
Segment Reporting Information [Line Items]
Revenues	1,022	736	857
Depreciation and amortization	231	231	226
Operating income	236	215	202
Other Income (deductions)	(10)	4	5
Interest charges	68	196	186
Income taxes on operating income	44	(43)	(58)
Total assets	6,554	6,848	6,528
Capital expenditures	298	616	248
Operating segment | Con Edison Transmission
Segment Reporting Information [Line Items]
Revenues	4	4	4
Depreciation and amortization	1	1	1
Operating income	(16)	(8)	(6)
Other Income (deductions)	(407)	(215)	104
Interest charges	9	18	25
Income taxes on operating income	3	0	1
Total assets	249	1,348	1,618
Capital expenditures	31	3	205
Operating segment | CECONY
Segment Reporting Information [Line Items]
Revenues	11,716	10,647	10,821
Depreciation and amortization	1,705	1,598	1,373
Operating income	2,460	2,310	2,348
Other Income (deductions)	(108)	(171)	(35)
Interest charges	762	739	728
Income taxes on operating income	252	218	342
Total assets	52,655	50,967	46,557
Capital expenditures	3,418	3,246	3,020
Operating segment | CECONY | Electric
Segment Reporting Information [Line Items]
Revenues	8,806	8,103	8,062
Depreciation and amortization	1,286	1,214	1,053
Operating income	1,802	1,731	1,758
Other Income (deductions)	(84)	(134)	(28)
Interest charges	542	535	539
Income taxes on operating income	151	130	239
Total assets	36,260	35,673	32,988
Capital expenditures	2,189	2,080	1,851
Operating segment | CECONY | Gas
Segment Reporting Information [Line Items]
Revenues	2,378	2,036	2,132
Depreciation and amortization	326	294	231
Operating income	646	574	528
Other Income (deductions)	(16)	(25)	(4)
Interest charges	179	164	147
Income taxes on operating income	110	102	99
Total assets	13,748	12,678	11,090
Capital expenditures	1,126	1,044	1,078
Operating segment | CECONY | Steam
Segment Reporting Information [Line Items]
Revenues	532	508	627
Depreciation and amortization	93	90	89
Operating income	12	5	62
Other Income (deductions)	(8)	(12)	(3)
Interest charges	41	40	42
Income taxes on operating income	(9)	(14)	4
Total assets	2,647	2,616	2,479
Capital expenditures	103	122	91
Operating segment | O&R
Segment Reporting Information [Line Items]
Revenues	941	862	893
Depreciation and amortization	95	90	84
Operating income	150	147	139
Other Income (deductions)	(12)	(14)	(11)
Interest charges	42	41	41
Income taxes on operating income	21	21	21
Total assets	3,292	3,247	3,006
Capital expenditures	217	220	203
Operating segment | O&R | Electric
Segment Reporting Information [Line Items]
Revenues	681	629	634
Depreciation and amortization	69	65	60
Operating income	100	99	98
Other Income (deductions)	(8)	(10)	(7)
Interest charges	27	26	27
Income taxes on operating income	13	13	15
Total assets	2,123	2,097	2,130
Capital expenditures	147	159	142
Operating segment | O&R | Gas
Segment Reporting Information [Line Items]
Revenues	260	233	259
Depreciation and amortization	26	25	24
Operating income	50	48	41
Other Income (deductions)	(4)	(4)	(4)
Interest charges	15	15	14
Income taxes on operating income	8	8	6
Total assets	1,169	1,150	876
Capital expenditures	70	61	61
Other
Segment Reporting Information [Line Items]
Revenues	(7)	(3)	(1)
Depreciation and amortization	0	0	0
Operating income	(4)	(10)	(7)
Other Income (deductions)	(1)	(5)	(12)
Interest charges	24	25	11
Income taxes on operating income	20	(3)	(6)
Total assets	366	485	370
Capital expenditures	0	0	0
Other | O&R
Segment Reporting Information [Line Items]
Revenues	0	0	0
Depreciation and amortization	0	0	0
Operating income	0	0	0
Other Income (deductions)	0	0	0
Interest charges	0	0	0
Income taxes on operating income	0	0	0
Total assets	0	0	0
Capital expenditures	0	0	0
Inter-segment
Segment Reporting Information [Line Items]
Revenues	0	0	0
Inter-segment | Clean Energy Businesses
Segment Reporting Information [Line Items]
Revenues	0	0	0
Inter-segment | CECONY
Segment Reporting Information [Line Items]
Revenues	(100)	(99)	(94)
Inter-segment | CECONY | Electric
Segment Reporting Information [Line Items]
Revenues	18	18	17
Inter-segment | CECONY | Gas
Segment Reporting Information [Line Items]
Revenues	8	7	7
Inter-segment | CECONY | Steam
Segment Reporting Information [Line Items]
Revenues	$ 74	$ 74	$ 70