Fair Value Measurements (Changes In Level 3 Assets And (Liabilities) Measured At Fair Value On A Recurring Basis) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended				12 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011		Dec. 31, 2011	Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains and losses attributable to changes in net derivative assets and liabilities, included in OCI										$ (3)
Gains and losses attributable to changes in net derivative assets and liabilities, included in Income from Discontinued Operations									1	3
Gains and losses attributable to changes in net derivative assets and liabilities, unrealized					(7)
Purchases			37				55
Sales			(36)				(36)
Issuances	0		(9)		0		(20)
Settlements	(14)		6		(43)		(5)
PSEG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains and losses attributable to changes in net derivative assets and liabilities, included in Operating Income					7		41
Gains and losses attributable to changes in net derivative assets and liabilities, unrealized							(2)
Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Gains and losses attributable to changes in net derivative assets and liabilities, included in Operating Income									(7)	(40)
Gains and losses attributable to changes in net derivative assets and liabilities, included in OCI									(2)
Gains and losses attributable to changes in net derivative assets and liabilities, unrealized									(24)	(56)
Gains and losses attributable to changes in net derivative assets and liabilities, realized							8
Net Derivative Assets (Liabilities) [Member] | PSEG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Opening Balance	61		2		21		47		47
Included in Income	7	[1]	(9)	[1]	41		(40)
Included in Regulatory Assets/Liabilities	(90)	[2]	6	[2]	(55)	[2]	(4)	[2]
Purchases, (Sales)	0	[3]	1	[3]	0	[3]	19	[3]
Issuances (Settlements)	(14)	[4]	(3)	[4]	(43)	[4]	(25)	[4]
Transfers In (Out)	0	[5]	0	[5]	0	[5]	0	[5]
Closing Balance	(36)		(3)		(36)		(3)
Net Derivative Assets (Liabilities) [Member] | Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Opening Balance	29		7		24		42		42
Included in Income	7	[1]	(9)	[1]	41		(40)
Included in Regulatory Assets/Liabilities	0	[2]	0	[2]	0	[2]	0	[2]
Purchases, (Sales)	0	[3]	1	[3]	0	[3]	19	[3]
Issuances (Settlements)	(14)	[4]	(3)	[4]	(43)	[4]	(25)	[4]
Transfers In (Out)	0	[5]	0	[5]	0	[5]	0	[5]
Closing Balance	22		(4)		22		(4)
Net Derivative Assets (Liabilities) [Member] | PSE And G [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Opening Balance	32		(5)		(3)		5		5
Included in Income	0	[1]	0	[1]	0		0
Included in Regulatory Assets/Liabilities	(90)	[2]	6	[2]	(55)	[2]	(4)	[2]
Purchases, (Sales)	0	[3]	0	[3]	0	[3]	0	[3]
Issuances (Settlements)	0	[4]	0	[4]	0	[4]	0	[4]
Transfers In (Out)	0	[5]	0	[5]	0	[5]	0	[5]
Closing Balance	(58)		1		(58)		1
NDT Funds [Member] | PSEG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Opening Balance							8		8
Included in Income							0
Included in Regulatory Assets/Liabilities							0	[2]
Purchases, (Sales)							0	[3]
Issuances (Settlements)							0	[4]
Transfers In (Out)							(8)	[5]
Closing Balance			0				0
NDT Funds [Member] | Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Opening Balance							8		8
Included in Income							0
Included in Regulatory Assets/Liabilities							0	[2]
Purchases, (Sales)							0	[3]
Issuances (Settlements)							0	[4]
Transfers In (Out)							(8)	[5]
Closing Balance			0				0
Non-Recourse Debt [Member] | PSEG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Opening Balance	(50)				(50)
Included in Income	50	[1]			50
Included in Regulatory Assets/Liabilities	0	[2]			0	[2]
Purchases, (Sales)	0	[3]			0	[3]
Issuances (Settlements)	0	[4]			0	[4]
Transfers In (Out)	0	[5]			0	[5]
Closing Balance	$ 0				$ 0

[1] PSEG's and Power's gains and losses attributable to changes in net derivative assets and liabilities include $7 million and $(7) million in Operating Income in 2012 and 2011 respectively; $(2) million in OCI and less than $1 million in Income from Discontinued Operations in 2011. Of the $7 million in Operating Income in 2012, $(7) million is unrealized. Of the $(7) million in Operating Income in 2011, $(24) million is unrealized. Energy Holdings' release from its obligations under the non-recourse debt is included in PSEG's Operating Income and is offset by the write-off of the related assets.

[2] Mainly includes gains/losses on PSE&G's derivative contracts that are not included in either earnings or OCI, as they are deferred as a Regulatory Asset/Liability and are expected to be recovered from/returned to PSE&G's customers.

[3] Includes none in purchases and sales in 2012. Includes $37 million in purchases and $(36) million in sales for the three months ended June 30, 2011. Includes $55 million in purchases and $(36) in sales for the six months ended June 30, 2011.

[4] Includes $0 million and $(9) million in issuances and $(14) million and $6 million in settlements for the three months ended June 30, 2012 and 2011, respectively. Includes $0 million and $(20) million in issuances and $(43) million and $(5) million in settlements for the six months ended June 30, 2012 and 2011, respectively.

[5] There were no transfers among levels during the three months ended June 30, 2012 and 2011 and the six months ended June 30, 2012. During the six months ended June 30, 2011, $8 million of assets in the NDT fund were transferred from Level 3 to Level 2, due to more observable pricing for the underlying securities. The transfer was recognized as of the beginning of the first quarter (i.e. the quarter in which the transfer occurred), as per PSEG's policy.