Stock-Based Compensation (Summary Of Changes In The Status Of Performance RSU's) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011
TSR Portion [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at 12/31/10, shares	494,188
Weighted average grant date non-vested at 12/31/10	$ 37.844	[1]
Granted, shares	217,735
Weighted average date granted	$ 43.847	[1]
Vested, shares	(210,763)
Weighted average grant date vested	$ 33.256	[1]
Forfeited, shares	(26,643)
Weighted average grant date forfeited	$ 40.083	[1]
Non-vested at 12/31/11, shares	474,517
Weighted average grant date non-vested at 12/31/11	$ 42.511	[1]
EIP Portion [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested at 12/31/10, shares	494,188
Weighted average grant date non-vested at 12/31/10	$ 42.591	[2]
Granted, shares	217,735
Weighted average date granted	$ 50.053	[2]
Vested, shares	(210,763)
Weighted average grant date vested	$ 40.926	[2]
Forfeited, shares	(26,643)
Weighted average grant date forfeited	$ 44.288	[2]
Non-vested at 12/31/11, shares	474,517
Weighted average grant date non-vested at 12/31/11	$ 46.660	[2]

[1] * Fair value is determined using the Monte Carlo simulation described above. Weighted average grant date fair value does not reflect any accrual or payment of dividends prior to vesting.

[2] * Fair value is determined using the market price of one share of Con Edison common stock on the grant date. The market price has not been discounted to reflect that dividends do not accrue and are not payable on Performance RSUs until vesting.