Goodwill	12 Months Ended
Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill The Companies test goodwill for impairment at least annually or whenever there is a triggering event. There is an option to first make a qualitative assessment of whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount before applying a quantitative goodwill impairment test. The quantitative goodwill impairment test compares the estimated fair value of a reporting unit with its carrying value, including goodwill. If the estimated fair value of a reporting unit exceeds its carrying value, goodwill of the reporting unit is considered not impaired. If the carrying value exceeds the estimated fair value of the reporting unit, an impairment loss shall be recognized in an amount equal to that excess, limited to the total amount of goodwill allocated to that reporting unit.Con Edison has recorded goodwill related to the O&R merger, the acquisition of a gas storage company by CET Gas, and the acquisitions of a residential solar company and battery storage company by the Clean Energy Businesses. In 2020 and 2019, Con Edison completed impairment tests for their goodwill of $406 million related to the O&R merger and determined that it was not impaired. For the impairment test, $245 million and $161 million of goodwill were allocated to CECONY and O&R, respectively. In 2019, the Companies performed the optional qualitative assessment for goodwill related to the O&R merger. In 2020 and 2019, Con Edison completed impairment tests for goodwill of $8 million related to the gas storage company acquired by CET Gas, $14 million related to the residential solar company acquired by the Clean Energy Businesses and $18 million related to the battery storage company acquired by the Clean Energy Businesses, and determined that they were not impaired. Estimates of future cash flows, projected growth rates, and discount rates inherent in the cash flow estimates for Con Edison subsidiaries other than the Utilities may vary significantly from actual results, which could result in a future impairment of goodwill. The Companies identified no triggering events or changes in circumstances related to the COVID-19 pandemic that would indicate that the carrying value of goodwill may not be recoverable at December 31, 2020.

Goodwill

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill The Companies test goodwill for impairment at least annually or whenever there is a triggering event. There is an option to first make a qualitative assessment of whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount before applying a quantitative goodwill impairment test. The quantitative goodwill impairment test compares the estimated fair value of a reporting unit with its carrying value, including goodwill. If the estimated fair value of a reporting unit exceeds its carrying value, goodwill of the reporting unit is considered not impaired. If the carrying value exceeds the estimated fair value of the reporting unit, an impairment loss shall be recognized in an amount equal to that excess, limited to the total amount of goodwill allocated to that reporting unit.Con Edison has recorded goodwill related to the O&R merger, the acquisition of a gas storage company by CET Gas, and the acquisitions of a residential solar company and battery storage company by the Clean Energy Businesses. In 2020 and 2019, Con Edison completed impairment tests for their goodwill of $406 million related to the O&R merger and determined that it was not impaired. For the impairment test, $245 million and $161 million of goodwill were allocated to CECONY and O&R, respectively. In 2019, the Companies performed the optional qualitative assessment for goodwill related to the O&R merger. In 2020 and 2019, Con Edison completed impairment tests for goodwill of $8 million related to the gas storage company acquired by CET Gas, $14 million related to the residential solar company acquired by the Clean Energy Businesses and $18 million related to the battery storage company acquired by the Clean Energy Businesses, and determined that they were not impaired. Estimates of future cash flows, projected growth rates, and discount rates inherent in the cash flow estimates for Con Edison subsidiaries other than the Utilities may vary significantly from actual results, which could result in a future impairment of goodwill. The Companies identified no triggering events or changes in circumstances related to the COVID-19 pandemic that would indicate that the carrying value of goodwill may not be recoverable at December 31, 2020.