Stock-Based Compensation - Summary of Changes in Status of Time-Based Awards (Details) - Time-based Awards	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Units
Non-vested at beginning of period (in shares) | shares	64,870
Granted (in shares) | shares	23,000
Vested (in shares) | shares	(20,523)
Forfeited (in shares) | shares	(2,167)
Non-vested at end of period (in shares) | shares	65,180
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share) | $ / shares	$ 71.93
Granted (in dollars per share) | $ / shares	77.94
Vested (in dollars per share) | $ / shares	61.03
Forfeited (in dollars per share) | $ / shares	73.93
Non-vested at end of period (in dollars per share) | $ / shares	$ 77.42
CECONY
Units
Non-vested at beginning of period (in shares) | shares	61,420
Granted (in shares) | shares	21,400
Vested (in shares) | shares	(19,473)
Forfeited (in shares) | shares	(1,967)
Non-vested at end of period (in shares) | shares	61,380
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share) | $ / shares	$ 71.93
Granted (in dollars per share) | $ / shares	77.94
Vested (in dollars per share) | $ / shares	61.03
Forfeited (in dollars per share) | $ / shares	73.97
Non-vested at end of period (in dollars per share) | $ / shares	$ 77.42