Fair Value Measurements (Changes In Level 3 Assets And (Liabilities) Measured At Fair Value On A Recurring Basis) (Detail) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Settlements $ 1 $ (22)
Net Derivative Assets (Liabilities) [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Opening Balance 7 1
Included in Income [1] 1 (19)
Included in Regulatory Assets/Liabilities [2] 0 6
Purchases, (Sales) 0 0
Issuances (Settlements) [3] 1 (22)
Transfers In (Out) [4] 0 (1)
Closing Balance 7 3
Net Derivative Assets (Liabilities) [Member] | Power [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Opening Balance 7 6
Included in Income [1] 1 (19)
Included in Regulatory Assets/Liabilities [2] 0 0
Purchases, (Sales) 0 0
Issuances (Settlements) [3] 1 (22)
Transfers In (Out) [4] 0 (1)
Closing Balance 7 2
Net Derivative Assets (Liabilities) [Member] | PSE And G [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Opening Balance   (5)
Included in Income [1]   0
Included in Regulatory Assets/Liabilities [2]   6
Purchases, (Sales)   0
Issuances (Settlements) [3]   0
Transfers In (Out) [4]   0
Closing Balance   1
Operating Revenues [Member] | Power [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Gains and losses attributable to changes in net derivative assets and liabilities, included in Operating Income   14
Gains and losses attributable to changes in net derivative assets and liabilities, unrealized 8 (4)
Energy Costs [Member] | Power [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Gains and losses attributable to changes in net derivative assets and liabilities, included in Operating Income   5
Gains and losses attributable to changes in net derivative assets and liabilities, unrealized $ (9) $ 1
[1] PSEG’s and Power’s gains(losses) attributable to changes in net derivative assets and liabilities for the three months ended March 31, 2018 include $8 million in Operating Revenues, all of which is unrealized and $(9) million in Energy Costs, all of which is unrealized. For the three months ended March 31, 2017, $14 million is included in Operating Revenues, of which $(4) million is unrealized, and $5 million is in Energy Costs, of which $1 million is unrealized. Unrealized gains (losses) represent the change in derivative assets and liabilities still held at the end of the reporting period.
[2] Mainly includes gains/losses on PSE&G’s derivative contracts that are not included in either earnings or Accumulated Other Comprehensive Income, as they are deferred as a Regulatory Asset/Liability and are expected to be recovered from/returned to PSE&G’s customers.
[3] Represents $1 million and $(22) million in settlements for the three months ended March 31, 2018 and 2017, respectively.
[4] During the three months ended March 31, 2017, $(1) million of net derivatives were transferred from Level 2 to Level 3.