Consolidated Statement of Common Shareholders' Equity (USD $) In Millions, except Share data	Total	CECONY [Member]	Common Stock [Member]	Common Stock [Member] CECONY [Member]	Additional Paid-In Capital [Member]	Additional Paid-In Capital [Member] CECONY [Member]	Retained Earnings [Member]	Retained Earnings [Member] CECONY [Member]	Treasury Stock [Member]	Capital Stock Expense [Member]	Capital Stock Expense [Member] CECONY [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Accumulated Other Comprehensive Income/(Loss) [Member] CECONY [Member]	Noncontrolling Interest [Member]	Repurchased Con Edison Stock [Member] CECONY [Member]
BALANCE at Dec. 31, 2011		$ 10,218		$ 589		$ 4,234		$ 6,429			$ (64)		$ (8)		$ (962)
BALANCE at Dec. 31, 2011	11,436		32		4,991		7,568		(1,033)	(64)		(58)
BALANCE (in shares) at Dec. 31, 2011			292,888,521	235,488,094					23,194,075
Net income for common stock	1,138	1,014					1,138
NET INCOME	1,141	1,017						1,017
Common stock dividends	(709)	(682)					(709)	(682)
Issuance of common shares for stock plans, net of repurchases	(1)								(4)	3
Cumulative preferred dividends	(3)	(3)						(3)
Issuance of common shares for stock plans, net of repurchases (in shares)			(16,625)						16,625
Preferred stock redemption		3									3
Other comprehensive income	5	(1)										5	(1)
BALANCE at Dec. 31, 2012	11,869		32		4,991		7,997		(1,037)	(61)		(53)		0
BALANCE at Dec. 31, 2012		10,552		589		4,234		6,761			(61)		(9)		(962)
BALANCE (in shares) at Dec. 31, 2012			292,871,896	235,488,094					23,210,700
Net income for common stock	1,062	1,020					1,062
NET INCOME	1,062	1,020						1,020
Common stock dividends	(721)	(728)					(721)	(728)
Issuance of common shares for stock plans, net of repurchases	7				4				3
Issuance of common shares for stock plans, net of repurchases (in shares)			500						(500)
Other comprehensive income	28	3										28	3
BALANCE at Dec. 31, 2013	12,245		32		4,995		8,338		(1,034)	(61)		(25)		0
BALANCE at Dec. 31, 2013	12,245	10,847		589		4,234		7,053			(61)		(6)		(962)
BALANCE (in shares) at Dec. 31, 2013	292,872,396	235,488,094	292,872,396	235,488,094					23,210,200
Net income for common stock	1,092	1,058					1,092
NET INCOME	1,092	1,058						1,058
Common stock dividends	(739)	(712)					(739)	(712)
Issuance of common shares for stock plans, net of repurchases	(2)				(4)				2
Issuance of common shares for stock plans, net of repurchases (in shares)			3,800						(3,800)
Other comprehensive income	(20)	(5)										(20)	(5)
Noncontrolling interest	9													9
BALANCE at Dec. 31, 2014	12,585		32		4,991		8,691		(1,032)	(61)		(45)		9
BALANCE at Dec. 31, 2014	$ 12,576	$ 11,188		$ 589		$ 4,234		$ 7,399			$ (61)		$ (11)		$ (962)
BALANCE (in shares) at Dec. 31, 2014	292,876,196	235,488,094	292,876,196	235,488,094					23,206,400