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Commitments And Contingent Liabilities (Environmental Matters) (Detail)
$ in Millions
12 Months Ended
Dec. 31, 2017
USD ($)
Potentially_Responsible_Party
site
entity
Station
Plant
mi
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Site Contingency [Line Items]      
Percentage of residential gas supply permitted to be recovered in gas hedging by BPU 80.00%    
Number of miles related to the Passaic River constituting a facility as determined by the US Environmental Protection Agency | mi 17    
Number of legal entities contacted by EPA in conjunction with Newark Bay study area contamination | entity 11    
Number of operating electric generating stations located on Hackensack River | Station 2    
Number of former MGP contamination sites located on Hackensack river in conjunction with Newark Bay study area contamination | site 1    
Accrued environmental costs $ 357 $ 401  
Operation and Maintenance 2,869 3,008 $ 2,978
New England Generation Fleet 12,250 13,156  
Clean Energy Program Current $ 128 142  
PSE&G [Member]      
Site Contingency [Line Items]      
Percentage Of Cost Attributable To Potentially Responsible Party 7.60%    
Accrued environmental costs $ 283 332  
Regulatory Assets 3,433 3,518  
Operation and Maintenance 1,434 1,475 1,560
New England Generation Fleet 593 591  
Clean Energy Program Current 128 142  
Power [Member]      
Site Contingency [Line Items]      
Operation and Maintenance 1,038 1,143 $ 1,057
New England Generation Fleet 11,657 $ 12,565  
MGP Remediation Site Contingency [Member] | PSE&G [Member]      
Site Contingency [Line Items]      
Remediation liability recorded as other current liabilities 79    
Remediation liability recorded as environmental costs in noncurrent liabilities 279    
Regulatory Assets $ 358    
PSE&G's Former MGP Sites [Member]      
Site Contingency [Line Items]      
Number of MGP sites identified by registrant and the NJDEP requiring some level of remedial action | site 38    
PSE&G's Former MGP Sites [Member] | Power [Member]      
Site Contingency [Line Items]      
Percentage Of Cost Attributable To Potentially Responsible Party 1.90%    
Passaic River Site Contingency [Member]      
Site Contingency [Line Items]      
Estimated Cleanup Costs EPA Preferred Method $ 2,300    
Aggregate number of PRPs directed by the NJDEP to arrange for natural resource damage assessment and interim compensatory restoration along the lower Passaic River | Potentially_Responsible_Party 56    
Estimated cost of interim natural resource injury restoration $ 950    
Accrual for Environmental Loss Contingencies $ 57    
Passaic River Site Contingency [Member] | Transferred To Power From PSE&G [Member]      
Site Contingency [Line Items]      
Number of operating electric generating station (Essex Site) | Plant 1    
Passaic River Site Contingency [Member] | PSE&G [Member]      
Site Contingency [Line Items]      
Number of former generating electric station | Plant 1    
Number of former Manufactured Gas Plant (MGP) sites | Plant 4    
Accrual for Environmental Loss Contingencies $ 46    
Passaic River Site Contingency [Member] | Power [Member]      
Site Contingency [Line Items]      
Accrual for Environmental Loss Contingencies 11    
PennEast Natural Gas Pipeline [Member] | Power [Member]      
Site Contingency [Line Items]      
Terminated Guarantee 106    
Minimum [Member] | MGP Remediation Site Contingency [Member] | PSE&G [Member]      
Site Contingency [Line Items]      
Loss Contingency, Estimate of Possible Loss 358    
Accrual for Environmental Loss Contingencies 358    
Minimum [Member] | Passaic River Site Contingency [Member]      
Site Contingency [Line Items]      
Loss Contingency, Estimate of Possible Loss 518    
Maximum [Member] | MGP Remediation Site Contingency [Member] | PSE&G [Member]      
Site Contingency [Line Items]      
Loss Contingency, Estimate of Possible Loss 403    
Maximum [Member] | Passaic River Site Contingency [Member]      
Site Contingency [Line Items]      
Loss Contingency, Estimate of Possible Loss $ 3,200