Commitments And Contingent Liabilities (Basic Generation Service (BGS) And Basic Gas Supply Service (BGSS)) (Detail)	9 Months Ended
	Sep. 30, 2012
Long-term Purchase Commitment [Line Items]
Number of cubic feet in gas hedging permitted to be recovered by BPU	115,000,000,000
Percentage of residential gas supply permitted to be recovered in gas hedging by BPU	80.00%
Percentage of annual residential gas supply requirements to be hedged	50.00%
Number of cubic feet to be hedged	70,000,000,000
PSE And G [Member] | Auction Year 2009 [Member]
Long-term Purchase Commitment [Line Items]
36-Month Terms Ending	May 01, 2012
Load (MW)	2,900
$ per kWh	0.10372
PSE And G [Member] | Auction Year 2010 [Member]
Long-term Purchase Commitment [Line Items]
36-Month Terms Ending	May 01, 2013
Load (MW)	2,800
$ per kWh	0.09577
PSE And G [Member] | Auction Year 2011 [Member]
Long-term Purchase Commitment [Line Items]
36-Month Terms Ending	May 01, 2014
Load (MW)	2,800
$ per kWh	0.09430
PSE And G [Member] | Auction Year 2012 [Member]
Long-term Purchase Commitment [Line Items]
36-Month Terms Ending	May 01, 2015	[1]
Load (MW)	2,900
$ per kWh	0.08388

[1] Prices set in the 2012 BGS auction became effective on June 1, 2012 when the 2009 BGS auction agreements expired.