Financial Risk Management Activities (Schedule Of Derivative Instruments Fair Value In Balance Sheets) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	$ 123		$ 156
Derivative Contracts, Noncurrent Assets	144		106
Total Mark-to-Market Derivative Assets	267		262
Derivative Contracts, Current Liabilities	(51)		(131)
Derivative Contracts, Noncurrent Liabilities	(112)		(26)
Total Mark-to-Market Derivative (Liabilities)	(163)		(157)
Net Mark-to-Market Derivative Assets (Liabilities)	104		105
Net cash collateral received in connection with net derivative contracts	2		82
Power [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	102		139
Derivative Contracts, Noncurrent Assets	22		55
Total Mark-to-Market Derivative Assets	124		194
Derivative Contracts, Current Liabilities	(51)		(124)
Derivative Contracts, Noncurrent Liabilities	(6)		(24)
Total Mark-to-Market Derivative (Liabilities)	(57)		(148)
Net Mark-to-Market Derivative Assets (Liabilities)	67		46
Power [Member] | Netting [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	(255)	[1]	(448)	[1]
Derivative Contracts, Noncurrent Assets	(59)	[1]	(74)	[1]
Total Mark-to-Market Derivative Assets	(314)	[1]	(522)	[1]
Derivative Contracts, Current Liabilities	255	[1]	387	[1]
Derivative Contracts, Noncurrent Liabilities	57	[1]	53	[1]
Total Mark-to-Market Derivative (Liabilities)	312	[1]	440	[1]
Net Mark-to-Market Derivative Assets (Liabilities)	(2)	[1]	(82)	[1]
Power [Member] | Energy-Related Contracts [Member] | Cash Flow Hedging [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	3		55
Derivative Contracts, Noncurrent Assets	0		8
Total Mark-to-Market Derivative Assets	3		63
Derivative Contracts, Current Liabilities	(3)		(5)
Derivative Contracts, Noncurrent Liabilities	0		(1)
Total Mark-to-Market Derivative (Liabilities)	(3)		(6)
Net Mark-to-Market Derivative Assets (Liabilities)	0		57
PSE And G [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	3		0
Derivative Contracts, Noncurrent Assets	70		4
Derivative Contracts, Current Liabilities	0		(7)
Derivative Contracts, Noncurrent Liabilities	(106)		0
PSEG [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Liabilities			(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	52		47
Total Mark-to-Market Derivative Assets	70		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)	70		62
Not Designated as Hedging Instrument [Member] | Power [Member] | Energy-Related Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	354		532
Derivative Contracts, Noncurrent Assets	81		121
Total Mark-to-Market Derivative Assets	435		653
Derivative Contracts, Current Liabilities	(303)		(506)
Derivative Contracts, Noncurrent Liabilities	(63)		(76)
Total Mark-to-Market Derivative (Liabilities)	(366)		(582)
Net Mark-to-Market Derivative Assets (Liabilities)	69		71
Not Designated as Hedging Instrument [Member] | PSE And G [Member] | Energy-Related Contracts [Member]
Derivatives, Fair Value [Line Items]
Derivative Contracts, Current Assets	3		0
Derivative Contracts, Noncurrent Assets	70		4
Total Mark-to-Market Derivative Assets	73		4
Derivative Contracts, Current Liabilities	0		(7)
Derivative Contracts, Noncurrent Liabilities	(106)		0
Total Mark-to-Market Derivative (Liabilities)	(106)		(7)
Net Mark-to-Market Derivative Assets (Liabilities)	(33)		(3)
Current Assets [Member]
Derivatives, Fair Value [Line Items]
Net cash collateral received in connection with net derivative contracts	(4)		(77)
Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Net cash collateral received in connection with net derivative contracts	(2)		(23)
Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Net cash collateral received in connection with net derivative contracts	4		16
Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Net cash collateral received in connection with net derivative contracts			$ 2

[1] Represents the netting of fair value balances with the same counterparty (where the right of offset exists) and the application of collateral. As of September 30, 2012 and December 31, 2011, net cash collateral received of $2 million and $82 million, respectively, was netted against the corresponding net derivative contract positions. Of the $2 million as of September 30, 2012, cash collateral of $(4) million and $(2) million were netted against current assets and noncurrent assets, respectively, and cash collateral of $4 million was netted against current liabilities. Of the $82 million as of December 31, 2011, cash collateral of $(77) million and $(23) million were netted against current assets and noncurrent assets, respectively, and cash collateral of $16 million and $2 million were netted against current liabilities and noncurrent liabilities, respectively.