Fair Value Measurements (Schedule Of Quantitative Information About Level 3 Fair Value Measurements) (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2013		Dec. 31, 2012
Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 6		$ 13
Liabilities, Fair Value	0		4
PSE And G [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	97		67
Liabilities, Fair Value	138		107
PSEG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	103		80
Liabilities, Fair Value	138		111
Electric Swaps [Member] | Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	2		7
Liabilities, Fair Value	3		(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	1		1
Liabilities, Fair Value	(3)		(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	3	[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	97	[2]	67	[2]
Liabilities, Fair Value	$ (138)	[2]	$ (107)	[2]
Valuation Technique (s)	Discounted cash flow	[2]	Discounted cash flow	[2]
Significant Unobservable Inputs	Long-Term Gas Basis and Capacity Prices	[2]	Long-Term Gas Basis and Capacity Prices	[2]
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
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
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	0		0

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

[2] Includes long-term gas supply and long-term electric capacity positions with various unobservable inputs. Significant unobservable inputs for the gas supply contracts include long-term basis prices in the range of $0 to $4/MMBTU of natural gas. Unobservable inputs for the long-term electric capacity contracts include forecasted capacity prices in the range of $100 to $400/MW day.