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
		Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Included in Income		$ 13	$ 1
Settlements		(1)	(4)
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)		12	(3)
Net Derivative Assets (Liabilities) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Closing Balance		19	(2)
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	$ 1
Included in Income	[1]	13	1
Purchases, (Sales)		0	0
Issuances (Settlements)	[2]	(1)	(4)
Transfers In (Out)	[3]	0	0
Operating Revenues [Member] | PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Included in Income		18	6
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)		11	0
Energy Costs [Member] | PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Included in Income		1	(3)
Fair Value, Net Derivative Asset (Liability), Recurring Basis, Still Held, Unrealized Gain (Loss)		$ (5)	$ (5)

[1] Unrealized gains (losses) in the following table represent the change in derivative assets and liabilities still held as of March 31, 2020 and 2019. .                         Three Months Ended March 31,       2020   2019       Total Gains (Losses)   Unrealized Gains (Losses)   Total Gains (Losses)   Unrealized Gains (Losses)       Millions     PSEG and PSEG Power                   Operating Revenues $ 18
  $ 11
  $ 6
  $ —
    Energy Costs (5 )   1
  (5 )   (3 )     Total $ 13
  $ 12
  $ 1
  $ (3 )                      

[2] settlements of $(1) million for the three months ended March 31, 2020 and $(4) million for the three months ended March 31, 2019.

[3] There were no transfers into or out of Level 3 during the three months ended March 31, 2020 and 2019.