Consolidated Statement Of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
NET INCOME	$ 280	$ 314
OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES
Pension plan liability adjustments	7	3
TOTAL OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES	7	3
COMPREHENSIVE INCOME	287	317
Preferred stock dividend requirements of subsidiary	(3)	(3)
COMPREHENSIVE INCOME FOR COMMON STOCK	284	314
CECONY [Member]
NET INCOME	276	271
OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES
Pension plan liability adjustments
TOTAL OTHER COMPREHENSIVE INCOME/(LOSS), NET OF TAXES
COMPREHENSIVE INCOME	276	271
Preferred stock dividend requirements of subsidiary	$ (3)	$ (3)