Financial Risk Management Activities (Schedule Providing Credit Risk From Others, Net Of Collateral) (Detail) - PSEG Power LLC $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) Counterparty
Derivative [Line Items]
Current Exposure	$ 377
Collateral held from counterparties	39
Net Credit Exposure With Counterparties After Applying Collateral	338
Number of Counterparties greater than 10%	2
Net Exposure of Counterparties greater than 10%	$ 209
Number of active counterparties on credit risk derivatives | Counterparty	135
Investment Grade External Rating [Member]
Derivative [Line Items]
Credit exposure, percentage	88.00%
Investment Grade [Member]
Derivative [Line Items]
Current Exposure	$ 337
Collateral held from counterparties	39
Net Credit Exposure With Counterparties After Applying Collateral	298
Number of Counterparties greater than 10%	1
Net Exposure of Counterparties greater than 10%	169
Non-Investment Grade [Member]
Derivative [Line Items]
Current Exposure	40
Collateral held from counterparties	0
Net Credit Exposure With Counterparties After Applying Collateral	40
Number of Counterparties greater than 10%	1
Net Exposure of Counterparties greater than 10%	40
Cash [Member]
Derivative [Line Items]
Collateral held from counterparties	4
Letter of Credit [Member]
Derivative [Line Items]
Collateral held from counterparties	35
Public Service Electric and Gas Company | Investment Grade [Member]
Derivative [Line Items]
Net Exposure of Counterparties greater than 10%	169
Other [Member] | Investment Grade [Member]
Derivative [Line Items]
Net Exposure of Counterparties greater than 10%	$ 40