Variable Interest Entities (VIEs) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Variable Interest Entity [Line Items]
Operating Revenues	$ 2,421	$ 2,076	$ 6,176	$ 4,389
Operation and Maintenance	744	751	1,487	1,545
Long Island ServCo [Member]
Variable Interest Entity [Line Items]
Operating Revenues	129	129	257	252
Operation and Maintenance	$ 129	$ 129	$ 257	$ 252