Fair Value Measurements (Schedule Of Quantitative Information About Level 3 Fair Value Measurements) (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 30, 2013		Dec. 31, 2012
Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 8		$ 13
Liabilities, Fair Value	2		4
PSE And G [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	88		67
Liabilities, Fair Value	140		107
PSEG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	96		80
Liabilities, Fair Value	142		111
Electric Swaps [Member] | Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	7		7
Liabilities, Fair Value	0		(1)
Valuation Technique (s)	Discounted Cash Flow		Discounted Cash Flow
Significant Unobservable Inputs	Power Basis		Power Basis
Electric Load Deals [Member] | Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	0		1
Liabilities, Fair Value	(2)		(2)
Valuation Technique (s)	Discounted Cash Flow		Discounted Cash Flow
Significant Unobservable Inputs	Historic Load Variability		Historic Load Variability
Various [Member] | Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	1	[1]	5	[1]
Liabilities, Fair Value	0	[1]	(1)	[1]
Forward Contracts [Member] | PSE And G [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	88		67
Liabilities, Fair Value	$ (140)		$ (107)
Valuation Technique (s)	Discounted Cash Flow		Discounted Cash Flow
Significant Unobservable Inputs	Long-Term Capacity Prices and Transportation Costs		Long-Term Gas Basis and Capacity Prices
Minimum [Member] | Electric Load Deals [Member] | Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Historic Load Variability	(5.00%)		(5.00%)
Minimum [Member] | MMBTU [Member] | Long-Term Gas Supply [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Longer-Term Basis Range			0
Minimum [Member] | MW-Day [Member] | Long Term Electric Capacity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Forecasted capacity prices	100		100
Minimum [Member] | Dekatherm [Member] | Long-Term Gas Supply [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Longer-Term Basis Range	1
Minimum [Member] | MWh [Member] | Electric Swaps [Member] | Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Power Basis Range	0		0
Maximum [Member] | Electric Load Deals [Member] | Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Historic Load Variability	10.00%		10.00%
Maximum [Member] | MMBTU [Member] | Long-Term Gas Supply [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Longer-Term Basis Range			4
Maximum [Member] | MW-Day [Member] | Long Term Electric Capacity [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Forecasted capacity prices	400		400
Maximum [Member] | Dekatherm [Member] | Long-Term Gas Supply [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Longer-Term Basis Range	1
Maximum [Member] | MWh [Member] | Electric Swaps [Member] | Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Power Basis Range	10		10

[1] Includes gas supply positions which are immaterial as of September 30, 2013 and December 31, 2012. Also includes long-term electric capacity positions which are immaterial as of December 31, 2012.