Financial Risk Management Activities (Schedule Of Derivative Instruments Fair Value In Balance Sheets) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	$ 77	$ 138
Derivative Contracts, Noncurrent Assets	102	153
Total Mark-to-Market Derivative Assets	179	291
Derivative Contracts, Current Liabilities	(27)	(46)
Derivative Contracts, Noncurrent Liabilities	(123)	(122)
Total Mark-to-Market Derivative (Liabilities)	(150)	(168)
Net Mark-to-Market Derivative Assets (Liabilities)	29	123
Net cash collateral received in connection with net derivative contracts	26	2
Power [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	52	118
Derivative Contracts, Noncurrent Assets	6	49
Total Mark-to-Market Derivative Assets	58	167
Derivative Contracts, Current Liabilities	(27)	(46)
Derivative Contracts, Noncurrent Liabilities	(14)	(15)
Total Mark-to-Market Derivative (Liabilities)	(41)	(61)
Net Mark-to-Market Derivative Assets (Liabilities)	17	106
Power [Member] | Netting [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	(304)	(217)
Derivative Contracts, Noncurrent Assets	(44)	(26)
Total Mark-to-Market Derivative Assets	(348)	(243)
Derivative Contracts, Current Liabilities	316	219
Derivative Contracts, Noncurrent Liabilities	58	26
Total Mark-to-Market Derivative (Liabilities)	374	245
Net Mark-to-Market Derivative Assets (Liabilities)	26	2
Power [Member] | Energy-Related Contracts [Member] | Cash Flow Hedging [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	0	3
Derivative Contracts, Noncurrent Assets	0	0
Total Mark-to-Market Derivative Assets	0	3
Derivative Contracts, Current Liabilities	0	0
Derivative Contracts, Noncurrent Liabilities	0	0
Total Mark-to-Market Derivative (Liabilities)	0	0
Net Mark-to-Market Derivative Assets (Liabilities)	0	3
PSE And G [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	10	5
Derivative Contracts, Noncurrent Assets	59	62
Derivative Contracts, Noncurrent Liabilities	(109)	(107)
PSEG [Member] | Interest Rate Swap [Member] | Fair Value Hedging [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	15	15
Derivative Contracts, Noncurrent Assets	37	42
Total Mark-to-Market Derivative Assets	52	57
Derivative Contracts, Current Liabilities	0	0
Derivative Contracts, Noncurrent Liabilities	0	0
Total Mark-to-Market Derivative (Liabilities)	0	0
Net Mark-to-Market Derivative Assets (Liabilities)	52	57
Not Designated as Hedging Instrument [Member] | Power [Member] | Energy-Related Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	356	332
Derivative Contracts, Noncurrent Assets	50	75
Total Mark-to-Market Derivative Assets	406	407
Derivative Contracts, Current Liabilities	(343)	(265)
Derivative Contracts, Noncurrent Liabilities	(72)	(41)
Total Mark-to-Market Derivative (Liabilities)	(415)	(306)
Net Mark-to-Market Derivative Assets (Liabilities)	(9)	101
Not Designated as Hedging Instrument [Member] | PSE And G [Member] | Energy-Related Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	10	5
Derivative Contracts, Noncurrent Assets	59	62
Total Mark-to-Market Derivative Assets	69	67
Derivative Contracts, Current Liabilities	0	0
Derivative Contracts, Noncurrent Liabilities	(109)	(107)
Total Mark-to-Market Derivative (Liabilities)	(109)	(107)
Net Mark-to-Market Derivative Assets (Liabilities)	(40)	(40)
Current Assets [Member]
Derivatives, Fair Value [Line Items]
Net cash collateral received in connection with net derivative contracts	12	(3)
Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Net cash collateral received in connection with net derivative contracts	$ 14	$ 5