Variable Interest Entities (VIEs) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Operating Revenues	$ 9,800	$ 9,722	$ 9,603
Operation and Maintenance	3,178	3,226	3,115
Long Island ServCo [Member]
Variable Interest Entity [Line Items]
Operating Revenues	516	511	520
Operation and Maintenance	516	511	$ 520
Ocean Wind JV Holdco
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	225	111
Ocean Wind JV Holdco | Carrying Value
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 225	$ 111