Fair Value Measurements (Changes In Level 3 Assets And (Liabilities) Measured At Fair Value On A Recurring Basis) (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	Jun. 30, 2019	Dec. 31, 2018
PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Included in Income		$ (2)	$ 2	$ 7	$ 10
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)		(10)	(2)	(7)	1
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements		(8)	(3)	(14)	(9)
Net Derivative Assets (Liabilities) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Closing Balance		0		0
Net Derivative Assets (Liabilities) [Member] | PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value						$ 7	$ 4	$ 1
Opening Balance		10
Included in Income	[1]	2	(1)	7	10
Purchases, (Sales)		0	0	0	0
Issuances (Settlements)	[2]	(8)	(4)	(14)	(10)
Transfers In (Out)	[3]	0	0	0	0
Closing Balance		0	1	0	1
Operating Revenues [Member] | PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Included in Income		(2)	(2)	12	14
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)		(11)	(4)	(9)	5
Energy Costs [Member] | PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Included in Income		0	4	(5)	(4)
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)		$ 1	$ 2	$ 2	$ (4)

[1] Unrealized gains (losses) in the following table represent the change in derivative assets and liabilities still held as of September 30, 2020 and 2019.. Three Months Ended September 30,Nine Months Ended September 30,2020201920202019Total Gains (Losses)Unrealized Gains (Losses)Total Gains (Losses)Unrealized Gains (Losses)Total Gains (Losses)Unrealized Gains (Losses)Total Gains (Losses)Unrealized Gains (Losses)MillionsPSEG and PSEG PowerOperating Revenues$(2)$(11)$(2)$(4)$12 $(9)$14 $5 Energy Costs— 1 4 2 (5)2 (4)(4)Total$(2)$(10)$2 $(2)$7 $(7)$10 $1 

[2] 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.

[3] There were no transfers into or out of Level 3 during the three months and nine months ended September 30, 2020 and 2019.