Fair Value Measurements (Narrative) (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020	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		$ 3,400	$ 2,700
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		(1)
Net Derivative Assets [Member] | PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Issuances (Settlements)	[1]	(4)	(1)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs			$ 19
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		$ 2

[1] Includes settlements of $(4) million for the three months ended March 31, 2021 and $(1) million for the three months ended March 31, 2020, respectively.