Consolidated Statement of Shareholders' 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, 2013		293,000,000								235,000,000
BALANCE AS OF BEGINNING OF PERIOD at Dec. 31, 2013	$ 12,245	$ 32	$ 4,995	$ 8,338	$ (1,034)	$ (61)	$ (25)	$ 0
BALANCE AS OF BEGINNING OF PERIOD at Dec. 31, 2013									$ 10,847	$ 589	$ 4,234	$ 7,053	$ (962)	$ (61)	$ (6)
TREASURY STOCK, BALANCE AS OF BEGINNING OF PERIOD (in shares) at Dec. 31, 2013					23,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,092			1,092					1,058			1,058
Common stock dividends	(739)			(739)					(712)			(712)
Issuance of common shares for stock plans, net of repurchases (in shares)		0			0
Issuance of common shares for stock plans, net of repurchases	(2)		(4)		$ 2
Other comprehensive income (loss)	(20)						(20)		(5)						(5)
Noncontrolling interest	9							9
BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2014		293,000,000								235,000,000
BALANCE AS OF END OF PERIOD at Dec. 31, 2014	12,585	$ 32	4,991	8,691	$ (1,032)	(61)	(45)	9							(11)
BALANCE AS OF END OF PERIOD at Dec. 31, 2014									11,188	$ 589	4,234	7,399	(962)	(61)	(11)
TREASURY STOCK, BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2014					23,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,193			1,193					1,084			1,084
Common stock dividends	(761)			(761)					(872)			(872)
Issuance of common shares for stock plans, net of repurchases (in shares)		0			0
Issuance of common shares for stock plans, net of repurchases	33		39		$ (6)
Capital contribution by parent									13		13
Other comprehensive income (loss)	11						11		2						2
Noncontrolling interest	0							0
BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2015		293,000,000								235,000,000
BALANCE AS OF END OF PERIOD at Dec. 31, 2015	13,061	$ 32	5,030	9,123	$ (1,038)	(61)	(34)	9							(9)
BALANCE AS OF END OF PERIOD at Dec. 31, 2015	13,052								11,415	$ 589	4,247	7,611	(962)	(61)	(9)
TREASURY STOCK, BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2015					23,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,245			1,245					1,056			1,056
Common stock dividends	(809)			(809)					(744)			(744)
Issuance of common shares - public offering (in shares)		10,000,000
Issuance of common shares - public offering	702	$ 1	723			(22)
Issuance of common shares for stock plans (in shares)		2,000,000
Issuance of common shares for stock plans	101		101
Capital contribution by parent									100		100
Other comprehensive income (loss)	7						7		$ 2						2
Noncontrolling interest	(1)							(1)
BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2016		305,000,000							21,976,200	235,000,000
BALANCE AS OF END OF PERIOD at Dec. 31, 2016	14,306	$ 33	$ 5,854	$ 9,559	$ (1,038)	$ (83)	$ (27)	$ 8							(7)
BALANCE AS OF END OF PERIOD at Dec. 31, 2016	$ 14,298								$ 11,829	$ 589	$ 4,347	$ 7,923	$ (962)	$ (61)	$ (7)
TREASURY STOCK, BALANCE AS OF END OF PERIOD (in shares) at Dec. 31, 2016					23,000,000