Variable Interest Entities (VIEs) (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Operating Revenues	$ 2,090	$ 2,450	$ 1,905	$ 2,616	$ 2,278	$ 2,688	$ 2,314	$ 3,135	$ 9,061	$ 10,415	$ 10,886
Operation and Maintenance									3,008	2,978	3,150
PSE&G [Member]
Variable Interest Entity [Line Items]
Operating Revenues	$ 1,475	$ 1,684	$ 1,350	$ 1,712	$ 1,402	$ 1,766	$ 1,466	$ 2,002	6,221	6,636	6,766
Operation and Maintenance									1,475	1,560	1,558
Long Island ServCo [Member]
Variable Interest Entity [Line Items]
Operating Revenues									410	375	389
Operation and Maintenance									$ 410	$ 375	$ 389