Stock-Based Compensation - Summary of Changes in Status of Performance RSUs' (Details) - Performance RSUs	12 Months Ended
Dec. 31, 2020 $ / shares shares
Units
Non-vested at beginning of period (in shares) \| shares	991,238
Granted (in shares) \| shares	329,600
Vested (in shares) \| shares	(326,496)
Forfeited (in shares) \| shares	(92,818)
Non-vested at end of period (in shares) \| shares	901,524
CECONY
Units
Non-vested at beginning of period (in shares) \| shares	742,204
Granted (in shares) \| shares	249,761
Vested (in shares) \| shares	(245,269)
Forfeited (in shares) \| shares	(60,225)
Non-vested at end of period (in shares) \| shares	686,471
TSR Portion
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share)	$ 68.15
Granted (in dollars per share)	79.98
Vested (in dollars per share)	73.07
Forfeited (in dollars per share)	73.80
Non-vested at end of period (in dollars per share)	$ 70.11
Adjustment percentage used for Performance awards	50.00%
TSR Portion \| CECONY
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share)	$ 68.06
Granted (in dollars per share)	79.70
Vested (in dollars per share)	72.70
Forfeited (in dollars per share)	73.61
Non-vested at end of period (in dollars per share)	70.15
Non-TSR Portion
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share)	77.14
Granted (in dollars per share)	90.48
Vested (in dollars per share)	74.57
Forfeited (in dollars per share)	87.98
Non-vested at end of period (in dollars per share)	$ 81.83
Adjustment percentage used for Performance awards	50.00%
Non-TSR Portion \| CECONY
Weighted Average Grant Date Fair Value
Non-vested at beginning of period (in dollars per share)	$ 77.32
Granted (in dollars per share)	89.65
Vested (in dollars per share)	74.76
Forfeited (in dollars per share)	87.73
Non-vested at end of period (in dollars per share)	$ 81.80

Share Based Compensation Arrangement Percentage of RSU

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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