Schedule I Condensed Financial Information (Schedule Of Condensed Balance Sheet) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009		Dec. 31, 2008
Cash and temporary cash investments	$ 648		$ 338		$ 260		$ 74
Accounts receivable - other	1,123		1,173
Prepayments	145		341
Other current assets	159		178
Total Current Assets	3,638		3,669
Investments in subsidiaries and others	455		403
Goodwill	429		429
Other assets	10,028		8,413
Total Assets	39,214		36,348
Long-term debt due within one year	530		5
Accounts payable	961		1,151
Other current liabilities	468		454
Total Current Liabilities	2,987		2,530
Noncurrent Liabilities	5,831		4,270
Long-term debt	10,143		10,671
Common stock	11,436		11,061		10,249		9,698
TOTAL SHAREHOLDER'S EQUITY	11,649		11,274
Total Liabilities and Shareholders' Equity	39,214		36,348
Parent Company [Member]
Cash and temporary cash investments	205	[1]	222	[1]	80	[1]	17	[1]
Accounts receivable - other	93	[1]	123	[1]
Accounts receivable from affiliated companies	208	[1]
Prepayments	36	[1]	240	[1]
Other current assets	61	[1]	51	[1]
Total Current Assets	603	[1]	636	[1]
Investments in subsidiaries and others	12,145	[1]	11,807	[1]
Goodwill	406	[1]	406	[1]
Deferred income tax	19	[1]	38	[1]
Other assets	4	[1]	4	[1]
Total Assets	13,177	[1]	12,891	[1]
Long-term debt due within one year	1	[1]	1	[1]
Accounts payable	5	[1]	5	[1]
Accounts payable to affiliated companies	143	[1]	356	[1]
Other current liabilities	240	[1]	134	[1]
Total Current Liabilities	389	[1]	496	[1]
Noncurrent Liabilities		[1]		[1]
Total Liabilities	389	[1]	496	[1]
Long-term debt	313	[1]	314	[1]
Common stock	4,977	[1]	4,900	[1]
Retained earnings	7,498	[1]	7,181	[1]
TOTAL SHAREHOLDER'S EQUITY	12,475	[1]	12,081	[1]
Total Liabilities and Shareholders' Equity	$ 13,177	[1]	$ 12,891	[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.