Fair Value Measurements (Schedule Of Quantitative Information About Level 3 Fair Value Measurements) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013		Dec. 31, 2012
Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 2		$ 13
Liabilities, Fair Value	(19)		(4)
PSE And G [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	69		67
Liabilities, Fair Value	(109)		(107)
PSEG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	71		80
Liabilities, Fair Value	(128)		(111)
Electric Swaps [Member] | Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	0		7
Liabilities, Fair Value	(13)		(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	(6)		(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	2		5
Liabilities, Fair Value	0		(1)
Forward Contracts [Member] | PSE And G [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	69		67
Liabilities, Fair Value	$ (109)		$ (107)
Valuation Technique (s)	Discounted cash flow	[1]	Discounted cash flow
Significant Unobservable Inputs	Long-Term Gas Basis and Capacity Prices	[1]	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
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	2
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] Quantitative Information About Level 3 Fair Value Measurements CommodityLevel 3 Position Fair Value as of December 31, 2012 ValuationTechnique(s) SignificantUnobservable Input Range Assets (Liabilities) Millions Power Electricity Electric Swaps $7 $(1) Discounted cash flow Power Basis $0 to $10/MWh ElectricityElectric Load Contracts 1 (2) Discounted cash flow Historic Load Variability -5% to +10% OtherVarious (A) 5 (1) Total Power $13 $(4) PSE&G Gas and Capacity Forward Contracts (B) $67 $(107) Discounted cash flow Long-Term Gas Basis and Capacity Prices (B) Total PSE&G $67 $(107) TOTAL PSEG $80 $(111)