Consolidated Statement of Capitalization (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Pension plan liability adjustments, tax	$ (30)	$ (34)
Unrealized gains/(losses) on derivatives qualified as cash flow hedges, tax and reclassification adjustment	(2)	(2)
Preferred stock, no par value	$ 0	$ 0
Preferred Stock, stated per share amount	$ 5	$ 5
Preferred stock, shares authorized	1,915,319	1,915,319
Preferred stock		213
Cumulative Preferred Stock [Member]
Preferred stock (in shares)		1,915,319
Preferred stock, shares authorized	6,000,000	6,000,000
Preferred stock, par value	$ 100	$ 100
Preferred stock		175
Cumulative Preferred Stock [Member] | 4.65% Series C [Member]
Preferred stock (in shares)		153,296
Preferred stock		16
Cumulative Preferred Stock [Member] | 4.65% Series D [Member]
Preferred stock (in shares)		222,330
Preferred stock		22
CECONY [Member]
Pension plan liability adjustments, tax	(4)	(3)
Unrealized gains/(losses) on derivatives qualified as cash flow hedges, tax and reclassification adjustment	(2)	(2)
Preferred stock, no par value
Preferred Stock, stated per share amount	$ 5	$ 5
Preferred stock, shares authorized	1,915,319	1,915,319
Preferred stock		213
CECONY [Member] | Cumulative Preferred Stock [Member]
Preferred stock (in shares)		1,915,319
Preferred stock		175
CECONY [Member] | Cumulative Preferred Stock [Member] | 4.65% Series C [Member]
Preferred stock (in shares)		153,296
Preferred stock, shares authorized	6,000,000	6,000,000
Preferred stock, par value	$ 100	$ 100
Preferred stock		16
CECONY [Member] | Cumulative Preferred Stock [Member] | 4.65% Series D [Member]
Preferred stock (in shares)		222,330
Preferred stock, shares authorized	6,000,000	6,000,000
Preferred stock		$ 22