Variable Interest Entities (VIEs) (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Variable Interest Entity [Line Items]
Operating Revenues	$ 2,278	$ 2,688	$ 2,314	$ 3,135	$ 2,773	$ 2,641	$ 2,249	$ 3,223	$ 10,415	$ 10,886	$ 9,968
Operation and Maintenance									2,978	3,150	2,887
PSE&G [Member]
Variable Interest Entity [Line Items]
Operating Revenues	$ 1,402	$ 1,766	$ 1,466	$ 2,002	$ 1,531	$ 1,655	$ 1,435	$ 2,145	6,636	6,766	6,655
Operation and Maintenance									1,560	1,558	$ 1,639
Long Island ServCo [Member]
Variable Interest Entity [Line Items]
Operating Revenues									375	389
Operation and Maintenance									$ 375	$ 389