Available-For-Sale Securities (Fair Value Of Rabbi Trust) (Detail) - Rabbi Trust [Member] - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Total Rabbi Trust Available-for-Sale Securities	$ 231	$ 217
Power [Member]
Schedule of Available-for-sale Securities [Line Items]
Total Rabbi Trust Available-for-Sale Securities	57	53
PSE&G [Member]
Schedule of Available-for-sale Securities [Line Items]
Total Rabbi Trust Available-for-Sale Securities	46	43
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Total Rabbi Trust Available-for-Sale Securities	$ 128	$ 121