Fair Value Measurements (Narrative) (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 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		$ 4,400	$ 3,500	$ 4,400	$ 3,500
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		(3)		(3)
Net Derivative Assets [Member] | PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Issuances (Settlements)	[1]	5	(8)	3	(14)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs		(3)	$ 0	(3)	$ 0	$ (8)
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 $5 million and $3 million for the three months and nine months ended September 30, 2021, respectively, and $(8) million and $(14) million for the three months and nine months ended September 30, 2020, respectively.