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Fair Value Measurements (Schedule Of Quantitative Information About Level 3 Fair Value Measurements) (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Assets, Fair Value Disclosure $ 12 $ 7
Financial and Nonfinancial Liabilities, Fair Value Disclosure (5) (6)
PSE&G [Member]    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Assets, Fair Value Disclosure   0
Financial and Nonfinancial Liabilities, Fair Value Disclosure   (5)
Power [Member]    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Assets, Fair Value Disclosure 12 7
Financial and Nonfinancial Liabilities, Fair Value Disclosure $ (5) (1)
Forward Contracts [Member] | PSE&G [Member]    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Assets, Fair Value Disclosure   0
Financial and Nonfinancial Liabilities, Fair Value Disclosure   $ (5)
Fair Value Measurements, Valuation Techniques   Discounted Cash Flow
Fair Value Measurement With Significant Unobservable Inputs   Transportation Costs
Forward Contracts [Member] | Dekatherms [Member] | PSE&G [Member] | Minimum [Member]    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Transportation Costs 0.60
Forward Contracts [Member] | Dekatherms [Member] | PSE&G [Member] | Maximum [Member]    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Transportation Costs 0.80
Electric Load Contracts [Member] | Power [Member]    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Assets, Fair Value Disclosure $ 1 $ 7
Financial and Nonfinancial Liabilities, Fair Value Disclosure $ (3) $ (1)
Fair Value Measurements, Valuation Techniques Discounted Cash flow Discounted Cash Flow
Fair Value Measurement With Significant Unobservable Inputs Historic Load Variability Historic Load Variability
Electric Load Contracts [Member] | Power [Member] | Minimum [Member]    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Historic Load Variability 0.00% 0.00%
Electric Load Contracts [Member] | Power [Member] | Maximum [Member]    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Historic Load Variability 10.00% 10.00%
Various [Member] | Power [Member]    
Fair Value Inputs, Assets, Quantitative Information [Line Items]    
Assets, Fair Value Disclosure $ 11 [1] $ 0
Financial and Nonfinancial Liabilities, Fair Value Disclosure $ (2) [1] $ 0
[1] Includes gas positions which were immaterial.