Financial Risk Management Activities (Schedule Providing Credit Risk From Others, Net Of Collateral) (Detail) - PSEG Power LLC $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) Counterparty
Derivative [Line Items]
Current Exposure	$ 508
Collateral held from counterparties	26
Net Credit Exposure With Counterparties After Applying Collateral	482
Number of Counterparties greater than 10%	2
Net Exposure of Counterparties greater than 10%	$ 263
Number of active counterparties on credit risk derivatives | Counterparty	153
Investment Grade External Rating [Member]
Derivative [Line Items]
Credit exposure, percentage	99.00%
Investment Grade [Member]
Derivative [Line Items]
Current Exposure	$ 505
Collateral held from counterparties	26
Net Credit Exposure With Counterparties After Applying Collateral	479
Number of Counterparties greater than 10%	2
Net Exposure of Counterparties greater than 10%	263
Non-Investment Grade [Member]
Derivative [Line Items]
Current Exposure	3
Collateral held from counterparties	0
Net Credit Exposure With Counterparties After Applying Collateral	3
Number of Counterparties greater than 10%	0
Net Exposure of Counterparties greater than 10%	0
Cash [Member]
Derivative [Line Items]
Collateral held from counterparties	4
Letter of Credit [Member]
Derivative [Line Items]
Collateral held from counterparties	22
Public Service Electric and Gas Company | Investment Grade [Member]
Derivative [Line Items]
Net Exposure of Counterparties greater than 10%	213
Other [Member] | Investment Grade [Member]
Derivative [Line Items]
Net Exposure of Counterparties greater than 10%	$ 50