Fair Value Measurements (Narrative) (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net assets measured at fair value on a recurring basis		$ 3,500	$ 2,400	$ 3,500	$ 2,400
Net assets measured at fair value on a recurring basis measured using unobservable input and as Level 3			1		1
Net Derivative Assets [Member] | PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Issuances (Settlements)	[1]	(8)	$ (4)	(14)	$ (10)
Nuclear Decommissioning Trust (NDT) Fund [Member] | PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
NDT Fund Foreign Currency		$ 1		$ 1		$ 2

[1] Includes settlements of $(8) million and $(14) million for the three months and nine months ended September 30, 2020, respectively, and $(3) million and $(9) million for the three months and nine months ended September 30, 2019, respectively.