Consolidated Statement Of Capitalization (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
TOTAL COMMON SHAREHOLDERS' EQUITY BEFORE ACCUMULATED OTHER COMPREHENSIVE LOSS	$ 11,494	$ 11,101
TOTAL COMMON SHAREHOLDERS' EQUITY BEFORE ACCUMULATED OTHER COMPREHENSIVE LOSS (in shares)	292,888,521	291,616,334
Pension plan liability adjustments, net of taxes	(55)	(37)
Unrealized gains/(losses) on derivatives qualified as cash flow hedges, net of taxes and reclassification adjustment	(3)	(3)
TOTAL ACCUMULATED OTHER COMPREHENSIVE LOSS, NET OF TAXES	(58)	(40)
TOTAL COMMON SHAREHOLDERS' EQUITY	11,436	11,061
Preferred stock	213	213
CECONY [Member]
TOTAL COMMON SHAREHOLDERS' EQUITY BEFORE ACCUMULATED OTHER COMPREHENSIVE LOSS	10,226	9,929
TOTAL COMMON SHAREHOLDERS' EQUITY BEFORE ACCUMULATED OTHER COMPREHENSIVE LOSS (in shares)	235,488,094	235,488,094
Pension plan liability adjustments, net of taxes	(5)	(3)
Unrealized gains/(losses) on derivatives qualified as cash flow hedges, net of taxes and reclassification adjustment	(3)	(3)
TOTAL ACCUMULATED OTHER COMPREHENSIVE LOSS, NET OF TAXES	(8)	(6)
TOTAL COMMON SHAREHOLDERS' EQUITY	10,218	9,923
Preferred stock	213	213
Cumulative Preferred Stock [Member]
Preferred stock (in shares)	1,915,319	1,915,319
Preferred stock	175	175
Cumulative Preferred Stock [Member] | CECONY [Member]
Preferred stock (in shares)	1,915,319	1,915,319
Preferred stock	175	175
Cumulative Preferred Stock [Member] | 4.65% Series C
Preferred stock (in shares)	153,296	153,296
Preferred stock	16	16
Cumulative Preferred Stock [Member] | 4.65% Series C | CECONY [Member]
Preferred stock (in shares)	153,296	153,296
Preferred stock	16	16
Cumulative Preferred Stock [Member] | 4.65% Series D
Preferred stock (in shares)	222,330	222,330
Preferred stock	22	22
Cumulative Preferred Stock [Member] | 4.65% Series D | CECONY [Member]
Preferred stock (in shares)	222,330	222,330
Preferred stock	$ 22	$ 22