Financial Risk Management Activities (Narrative) (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax		$ (8)	$ (9)
Derivative, Fair Value, Net		20	44
Unrealized Loss to be Reclassified to Earnings During the Next Twelve Months		(3)
PSEG Power [Member]
Derivatives, Fair Value [Line Items]
Securities held as Collateral		37
Derivative, Fair Value, Amount Offset Against Collateral, Net	[1],[2]	31	8
Fair Value of Derivatives with credit-risk related contingent features		28	28
Aggregate fair value of derivative contracts in a liability position that contains triggers for additional collateral		2	3
Additional collateral aggregate fair value		26	25
Derivative, Fair Value, Net	[2]	$ 20	$ 44

[1] Represents the netting of fair value balances with the same counterparty (where the right of offset exists) and the application of collateral. All cash collateral (received) posted that has been allocated to derivative positions, where the right of offset exists, has been offset on the Condensed Consolidated Balance Sheets. As of March 31, 2021 and December 31, 2020, PSEG Power had net cash collateral (receipts) payments to counterparties of $98 million and $54 million, respectively. Of these net cash collateral (receipts) payments, $31 million and $8 million as of March 31, 2021 and December 31, 2020, respectively, were netted against the corresponding net derivative contract positions. Of the $31 million as of March 31, 2021, $(2) million was netted against current assets, $(12) million was netted against noncurrent assets, $44 million was netted against current liabilities and $1 million was netted against noncurrent liabilities. Of the $8 million as of December 31, 2020, $(13) million was netted against current assets and $21 million was netted against noncurrent liabilities.

[2] Substantially all of PSEG Power’s and PSEG’s derivative instruments are contracts subject to master netting agreements. Contracts not subject to master netting or similar agreements are immaterial and did not have any collateral posted or received as of March 31, 2021 and December 31, 2020.