Variable Interest Entities (VIEs) (Detail) - USD ($) $ in Millions	3 Months Ended								6 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Operating Revenues	$ 2,468	$ 2,394		$ 2,818	$ 2,107	$ 2,254	$ 2,142	$ 2,591	$ 2,016	$ 9,696	$ 9,094	$ 8,966
Operation and Maintenance										3,015	2,901	2,991
PSE&G [Member]
Variable Interest Entity [Line Items]
Operating Revenues	$ 1,645	$ 1,595	$ 1,386	$ 1,845	$ 1,575	$ 1,530	$ 1,393	$ 1,826		6,471	6,324	6,303
Operation and Maintenance										1,575	1,458	1,465
Long Island ServCo [Member]
Variable Interest Entity [Line Items]
Operating Revenues										458	438	410
Operation and Maintenance										$ 458	$ 438	$ 410