Fair Value Measurements (Narrative) (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net assets measured at fair value on a recurring basis		$ 2,900	$ 2,900	$ 2,900	$ 2,900
Net Derivative Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs		(8)		(8)
Net Derivative Assets [Member] | PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Issuances (Settlements)	[1]	2	(5)	(2)	(6)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs		(8)	$ 10	(8)	$ 10	$ (1)
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		$ 2		$ 2			$ 2

[1] Includes settlements of $2 million and $(2) million for the three months and six months ended June 30, 2021 and $(5) million and $(6) million for the three months and six months ended June 30, 2020.