Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 3,629	$ 3,300	$ 8,517	$ 7,551
Total revenues	3,595	3,220	8,393	7,495
Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	(34)	(80)	(124)	(56)
CECONY
Disaggregation of Revenue [Line Items]
Total revenues	3,340	2,996	7,782	6,967
Operating Segments | Con Edison Transmission
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1	1	2	2
Total revenues	1	1	2	2
Operating Segments | Con Edison Transmission | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	0	0	0	0
Operating Segments | CECONY
Disaggregation of Revenue [Line Items]
Total revenues	3,340	2,996	7,782	6,967
Operating Segments | CECONY | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,368	3,058	7,891	7,003
Total revenues	3,340	2,996	7,782	6,967
Operating Segments | CECONY | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(28)	(62)	(109)	(36)
Operating Segments | CECONY | Electric
Disaggregation of Revenue [Line Items]
Total revenues	2,581	2,370	5,267	4,812
Operating Segments | CECONY | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,565	2,381	5,333	4,807
Total revenues		2,370		4,812
Operating Segments | CECONY | Electric | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	16	(11)	(66)	5
Operating Segments | CECONY | Gas
Disaggregation of Revenue [Line Items]
Total revenues	653	538	2,055	1,781
Operating Segments | CECONY | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	696	587	2,095	1,812
Total revenues		538		1,781
Operating Segments | CECONY | Gas | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(43)	(49)	(40)	(31)
Operating Segments | CECONY | Steam
Disaggregation of Revenue [Line Items]
Total revenues	106	88	460	374
Operating Segments | CECONY | Steam | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	107	90	463	384
Total revenues		88		374
Operating Segments | CECONY | Steam | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(1)	(2)	(3)	(10)
Operating Segments | O&R
Disaggregation of Revenue [Line Items]
Total revenues	254	224	610	527
Operating Segments | O&R | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	260	241	624	546
Total revenues	254	224	610	527
Operating Segments | O&R | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(6)	(17)	(14)	(19)
Operating Segments | O&R | Electric
Disaggregation of Revenue [Line Items]
Total revenues	196	180	411	370
Operating Segments | O&R | Electric | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	196	189	414	379
Total revenues		180		370
Operating Segments | O&R | Electric | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	0	(9)	(3)	(9)
Operating Segments | O&R | Gas
Disaggregation of Revenue [Line Items]
Total revenues	58	44	199	157
Operating Segments | O&R | Gas | Subsidiaries
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	64	52	210	167
Total revenues		44		157
Operating Segments | O&R | Gas | Other revenues | Subsidiaries
Disaggregation of Revenue [Line Items]
Total revenues	(6)	(8)	(11)	(10)
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0	0	0
Total revenues	0	(1)	(1)	(1)
Other | Other revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ 0	$ (1)	$ (1)	$ (1)