Goodwill and Other Intangible Assets (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) business_acquisition	Dec. 31, 2015 USD ($) business_acquisition
Goodwill [Line Items]
Goodwill	$ 428	$ 429
Impairment charge	15
Finite lived intangible assets, accumulated amortization	6	4
Amortization of Intangible Assets	2
Intangibles Future Amortization:
Year 1	8
Year 2	8
Year 3	8
Year 4	8
Year 5	8
Other Intangible Assets
Goodwill [Line Items]
Finite lived intangible assets, net	5	2
Finite lived intangible assets, accumulated amortization	5	4
O&R Merger
Goodwill [Line Items]
Goodwill	$ 406	406
Energy Service and Gas Storage Companies
Goodwill [Line Items]
Goodwill		$ 23
Number of businesses acquired included in goodwill impairment test | business_acquisition	2	2
Impairment charge	$ 15
Impairment charge, net of tax	12
Power Purchase
Goodwill [Line Items]
Finite lived intangible assets, net	119
Finite lived intangible assets, accumulated amortization	1
CECONY
Goodwill [Line Items]
Goodwill	245	$ 245
O&R
Goodwill [Line Items]
Goodwill	161	$ 161
Con Edison Solutions and Con Edison Development | Energy Service and Gas Storage Companies
Goodwill [Line Items]
Goodwill	$ 23
Con Edison Solutions | Energy Service and Gas Storage Companies
Goodwill [Line Items]
Number of businesses acquired included in goodwill impairment test | business_acquisition	2
Con Edison Solutions | Residential Solar Company
Goodwill [Line Items]
Goodwill	$ 14