Schedule I Condensed Financial Information (Schedule Of Condensed Income Statement) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Other income (deductions), net of taxes	$ 17		$ 40		$ 31
Interest expense	(594)		(609)		(611)
Net income for common stock	1,051		992		868
Net Income Per Common Share - Basic	$ 3.59		$ 3.49		$ 3.16
Net Income Per Common Share - Diluted	$ 3.57		$ 3.47		$ 3.14
Dividends Declared Per Share Of Common Stock	$ 2.40		$ 2.38		$ 2.36
Average Number Of Shares Outstanding - Basic (in millions)	292.6		284.3		275.2
Average Number Of Shares Outstanding - Diluted (in millions)	294.4		285.9		276.3
Parent Company [Member]
Equity in earnings of subsidiaries	1,064	[1]	1,008	[1]	883	[1]
Other income (deductions), net of taxes	15	[1]	12	[1]	14	[1]
Interest expense	(28)	[1]	(28)	[1]	(29)	[1]
Net income for common stock	$ 1,051	[1]	$ 992	[1]	$ 868	[1]
Net Income Per Common Share - Basic	$ 3.59	[1]	$ 3.49	[1]	$ 3.16	[1]
Net Income Per Common Share - Diluted	$ 3.57	[1]	$ 3.47	[1]	$ 3.14	[1]
Dividends Declared Per Share Of Common Stock	$ 2.40	[1]	$ 2.38	[1]	$ 2.36	[1]
Average Number Of Shares Outstanding - Basic (in millions)	292.6	[1]	284.3	[1]	275.2	[1]
Average Number Of Shares Outstanding - Diluted (in millions)	294.4	[1]	285.9	[1]	276.3	[1]

[1] These financial statements, in which Con Edison's subsidiaries have been included using the equity method, should be read together with its consolidated financial statements and the notes thereto appearing above.