Consolidated Statement of Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Capital Stock Expense	Accumulated Other Comprehensive Income/(Loss)	Noncontrolling Interest	CECONY	CECONY Common Stock	CECONY Additional Paid-In Capital	CECONY Retained Earnings	CECONY Repurchased Con Edison Stock	CECONY Capital Stock Expense	CECONY Accumulated Other Comprehensive Income/(Loss)
BALANCE AS OF BEGINNING OF PERIOD (in shares) at Dec. 31, 2018		321,000,000								235,000,000
BALANCE AS OF BEGINNING OF PERIOD at Dec. 31, 2018	$ 16,839	$ 34	$ 7,117	$ 10,728	$ (1,038)	$ (99)	$ (16)	$ 113
BALANCE AS OF BEGINNING OF PERIOD at Dec. 31, 2018									$ 12,910	$ 589	$ 4,769	$ 8,581	$ (962)	$ (62)	$ (5)
TREASURY STOCK, BALANCE AS OF BEGINNING OF PERIOD (in shares) at Dec. 31, 2018					23,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,343								1,250			1,250
Net Income	1,440			1,343				97
Common stock dividends	(971)			(971)					(912)			(912)
Issuance of common shares - public offering (in shares)		12,000,000
Issuance of common shares - public offering	825	$ 1	835			(11)
Issuance of common shares for stock plans	102		102
Capital contribution by parent									900		900
Other comprehensive income	(3)						(3)		(1)						(1)
Noncontrolling interest	(19)							(19)
BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2019		333,000,000								235,000,000
BALANCE AS OF END OF PERIOD at Dec. 31, 2019	18,213	$ 35	8,054	11,100	$ (1,038)	(110)	(19)	191
BALANCE AS OF END OF PERIOD at Dec. 31, 2019									14,147	$ 589	5,669	8,919	(962)	(62)	(6)
TREASURY STOCK, BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2019					23,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,101								1,185			1,185
Net Income	1,144			1,101				43
Common stock dividends	(1,023)			(1,023)					(982)			(982)
Issuance of common shares - public offering (in shares)		9,000,000
Issuance of common shares - public offering	640	$ 1	641			(2)
Issuance of common shares for stock plans	113		113
Capital contribution by parent									500		500
Other comprehensive income	(6)						(6)		$ (1)						(1)
Noncontrolling interest	$ (16)							(16)
BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2020	342,297,534	342,000,000							235,488,094	235,000,000
BALANCE AS OF END OF PERIOD at Dec. 31, 2020	$ 19,065	$ 36	8,808	11,178	$ (1,038)	(112)	(25)	218
BALANCE AS OF END OF PERIOD at Dec. 31, 2020	18,847								$ 14,849	$ 589	6,169	9,122	(962)	(62)	(7)
TREASURY STOCK, BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2020					23,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,346								1,344			1,344
Net Income	1,193			1,346				(153)
Common stock dividends	(1,079)			(1,079)					(988)			(988)
Issuance of common shares - public offering (in shares)		10,000,000
Issuance of common shares - public offering	766	$ 1	775			(10)
Issuance of common shares for stock plans	127		127
Capital contribution by parent									1,100		1,100
Other comprehensive income	30						30		$ 7						7
Distributions to noncontrolling interests	(23)							(23)
Net proceeds from sale of equity interest	$ 257							257
BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2021	353,983,712	354,000,000							235,488,094	235,000,000
BALANCE AS OF END OF PERIOD at Dec. 31, 2021	$ 20,336	$ 37	$ 9,710	$ 11,445	$ (1,038)	$ (122)	$ 5	$ 299
BALANCE AS OF END OF PERIOD at Dec. 31, 2021	$ 20,037								$ 16,312	$ 589	$ 7,269	$ 9,478	$ (962)	$ (62)	$ 0
TREASURY STOCK, BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2021					23,000,000