Financial Risk Management Activities (Schedule Of Derivative Instruments Fair Value In Balance Sheets) (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	$ 165	$ 156
Derivative Contracts, Noncurrent Assets	133	106
Total Mark-to-Market Derivative Assets	298	262
Derivative Contracts, Current Liabilities	(88)	(131)
Derivative Contracts, Noncurrent Liabilities	(112)	(26)
Total Mark-to-Market Derivative (Liabilities)	(200)	(157)
Net Mark-to-Market Derivative Assets (Liabilities)	98	105
Net cash collateral received in connection with net derivative contracts	73	82
Power [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	146	139
Derivative Contracts, Noncurrent Assets	40	55
Total Mark-to-Market Derivative Assets	186	194
Derivative Contracts, Current Liabilities	(88)	(124)
Derivative Contracts, Noncurrent Liabilities	(8)	(24)
Total Mark-to-Market Derivative (Liabilities)	(96)	(148)
Net Mark-to-Market Derivative Assets (Liabilities)	90	46
Power [Member] | Netting [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	(339)	(448)
Derivative Contracts, Noncurrent Assets	(116)	(74)
Total Mark-to-Market Derivative Assets	(455)	(522)
Derivative Contracts, Current Liabilities	282	387
Derivative Contracts, Noncurrent Liabilities	100	53
Total Mark-to-Market Derivative (Liabilities)	382	440
Net Mark-to-Market Derivative Assets (Liabilities)	(73)	(82)
Power [Member] | Energy-Related Contracts [Member] | Cash Flow Hedging [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	5	55
Derivative Contracts, Noncurrent Assets	0	8
Total Mark-to-Market Derivative Assets	5	63
Derivative Contracts, Current Liabilities	0	(5)
Derivative Contracts, Noncurrent Liabilities	0	(1)
Total Mark-to-Market Derivative (Liabilities)	0	(6)
Net Mark-to-Market Derivative Assets (Liabilities)	5	57
PSE And G [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Noncurrent Assets	45	4
Derivative Contracts, Current Liabilities	0	(7)
Derivative Contracts, Noncurrent Liabilities	(104)	0
PSEG [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Liabilities	(50)	(50)
PSEG [Member] | Interest Rate Swap [Member] | Fair Value Hedging [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	18	17
Derivative Contracts, Noncurrent Assets	48	47
Total Mark-to-Market Derivative Assets	66	64
Derivative Contracts, Current Liabilities	0	0
Derivative Contracts, Noncurrent Liabilities	0	(2)
Total Mark-to-Market Derivative (Liabilities)	0	(2)
Net Mark-to-Market Derivative Assets (Liabilities)	66	62
Not Designated as Hedging Instrument [Member] | Power [Member] | Energy-Related Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	480	532
Derivative Contracts, Noncurrent Assets	156	121
Total Mark-to-Market Derivative Assets	636	653
Derivative Contracts, Current Liabilities	(370)	(506)
Derivative Contracts, Noncurrent Liabilities	(108)	(76)
Total Mark-to-Market Derivative (Liabilities)	(478)	(582)
Net Mark-to-Market Derivative Assets (Liabilities)	158	71
Not Designated as Hedging Instrument [Member] | PSE And G [Member] | Energy-Related Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	1	0
Derivative Contracts, Noncurrent Assets	45	4
Total Mark-to-Market Derivative Assets	46	4
Derivative Contracts, Current Liabilities	0	(7)
Derivative Contracts, Noncurrent Liabilities	(104)	0
Total Mark-to-Market Derivative (Liabilities)	(104)	(7)
Net Mark-to-Market Derivative Assets (Liabilities)	(58)	(3)
Current Assets [Member]
Derivatives, Fair Value [Line Items]
Net cash collateral received in connection with net derivative contracts	66	77
Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Net cash collateral received in connection with net derivative contracts	17	23
Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Net cash collateral received in connection with net derivative contracts	10	16
Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Net cash collateral received in connection with net derivative contracts	$ 0	$ 2