Schedule I Condensed Financial Information (Schedule Of Condensed Statement Of Cash Flows) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Net Income	$ 1,051		$ 992		$ 868
Other - net	51		207		(346)
Net Cash Flows from Operating Activities	3,137		2,381		2,466
Net Cash Flows Used in Investing Activities	(2,150)		(2,175)		(2,360)
Net payments of short-term debt					(363)
Retirement of long-term debt	(4)		(1,011)		(662)
Common shares issued	118		439		257
Common stock dividends	(693)		(629)		(601)
Net Cash Flows Used in Financing Activities	(677)		(128)		80
Net Change for the Period	310		78		186
BALANCE AT BEGINNING OF PERIOD	338		260		74
BALANCE AT END OF PERIOD	648		338		260
Parent Company [Member]
Net Income	1,051	[1]	992	[1]	868	[1]
Equity in earnings of subsidiaries	1,064	[1]	1,008	[1]	883	[1]
Other - net	(67)	[1]	(4)	[1]	85	[1]
Net Cash Flows from Operating Activities	646	[1]	690	[1]	762	[1]
Contributions to subsidiaries			(355)	[1]	(241)	[1]
Net Cash Flows Used in Investing Activities			(355)	[1]	(241)	[1]
Net payments of short-term debt					(110)	[1]
Retirement of long-term debt	(1)	[1]	(3)	[1]	(4)	[1]
Common shares issued	31	[1]	439	[1]	257	[1]
Common stock dividends	(693)	[1]	(629)	[1]	(601)	[1]
Net Cash Flows Used in Financing Activities	(663)	[1]	(193)	[1]	(458)	[1]
Net Change for the Period	(17)	[1]	142	[1]	63	[1]
BALANCE AT BEGINNING OF PERIOD	222	[1]	80	[1]	17	[1]
BALANCE AT END OF PERIOD	205	[1]	222	[1]	80	[1]
CECONY [Member]
Net Income	978		893		781
Other - net	170		11		(122)
Net Cash Flows from Operating Activities	2,933		2,205		2,222
Contributions to subsidiaries			355		211
Net Cash Flows Used in Investing Activities	(1,947)		(1,998)		(2,108)
Net payments of short-term debt					(253)
Retirement of long-term debt			(850)		(655)
Common stock dividends	(681)	[1]	(670)	[1]	(652)	[1]
Net Cash Flows Used in Financing Activities	(692)		(260)		(20)
Net Change for the Period	294		(53)		94
BALANCE AT BEGINNING OF PERIOD	78		131		37
BALANCE AT END OF PERIOD	372		78		131
O&R [Member]
Common stock dividends	(33)	[1]	(32)	[1]	(32)	[1]
Competitive Energy Businesses [Member]
Common stock dividends	$ (12)	[1]	$ (8)	[1]	$ (8)	[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.