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Fair Value Measurements (Schedule Of Quantitative Information About Level 3 Fair Value Measurements) (Detail) - USD ($)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2021
Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value $ 3 $ 12
Liabilities, Fair Value (4) (5)
PSEG Power [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value 3 12
Liabilities, Fair Value (4) (5)
Electric Load Contracts [Member] | PSEG Power [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value 3 12
Liabilities, Fair Value $ (1) $ 0
Valuation Technique used Discounted Cash Flow Discounted Cash Flow
Significant Unobservable Inputs Load Shaping Cost Load Shaping Cost
Historic Load Variability 4.00% 4.00%
Electric Load Contracts [Member] | Minimum [Member] | PSEG Power [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Historic Load Variability 0.00% 0.00%
Electric Load Contracts [Member] | Maximum [Member] | PSEG Power [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Historic Load Variability 11.00% 11.00%
Gas Physical Contract [Member] | PSEG Power [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value $ 0 $ 0
Liabilities, Fair Value $ (1) $ (2)
Valuation Technique used Discounted Cash Flow Discounted Cash Flow
Significant Unobservable Inputs Historical Basis Adjustment Historical Basis Adjustment
Average Historical Basis (10.00%) (43.00%)
Gas Physical Contract [Member] | Minimum [Member] | PSEG Power [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Average Historical Basis (2.00%) (60.00%)
Gas Physical Contract [Member] | Maximum [Member] | PSEG Power [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Average Historical Basis (30.00%) (30.00%)
Other (Futures Contracts) | PSEG Power [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets, Fair Value $ 0 $ 0
Liabilities, Fair Value $ (2) $ (3)