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		9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended	3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended				3 Months Ended				9 Months Ended								3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 PSEG [Member]	Sep. 30, 2012 PSEG [Member]	Sep. 30, 2011 Power [Member]	Sep. 30, 2011 Power [Member]	Dec. 31, 2011 Power [Member]	Sep. 30, 2012 Net Derivative Assets (Liabilities) [Member] PSEG [Member]		Sep. 30, 2011 Net Derivative Assets (Liabilities) [Member] PSEG [Member]		Sep. 30, 2012 Net Derivative Assets (Liabilities) [Member] PSEG [Member]		Sep. 30, 2011 Net Derivative Assets (Liabilities) [Member] PSEG [Member]		Sep. 30, 2012 Net Derivative Assets (Liabilities) [Member] Power [Member]		Sep. 30, 2011 Net Derivative Assets (Liabilities) [Member] Power [Member]		Sep. 30, 2012 Net Derivative Assets (Liabilities) [Member] Power [Member]		Sep. 30, 2011 Net Derivative Assets (Liabilities) [Member] Power [Member]		Sep. 30, 2012 Net Derivative Assets (Liabilities) [Member] PSE And G [Member]		Sep. 30, 2011 Net Derivative Assets (Liabilities) [Member] PSE And G [Member]		Sep. 30, 2012 Net Derivative Assets (Liabilities) [Member] PSE And G [Member]		Sep. 30, 2011 Net Derivative Assets (Liabilities) [Member] PSE And G [Member]		Sep. 30, 2011 NDT Funds [Member] PSEG [Member]		Sep. 30, 2011 NDT Funds [Member] Power [Member]		Sep. 30, 2012 Non Recourse Debt [Member] PSEG [Member]	Sep. 30, 2011 Non Recourse Debt [Member] PSEG [Member]	Sep. 30, 2012 Non Recourse Debt [Member] PSEG [Member]		Sep. 30, 2011 Non Recourse Debt [Member] PSEG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Opening Balance										$ 36		$ 3		$ (21)		$ (47)		$ (22)		$ 4		$ (24)		$ (42)		$ 58		$ (1)		$ 3		$ (5)		$ (8)		$ (8)				$ 50
Included in Income										(1)	[1]	13	[1]	40	[2]	(27)	[2]	(1)	[1]	13	[1]	40	[2]	(27)	[2]	0	[1]	0	[1]	0	[2]	0	[2]	0	[2]	0	[2]			50	[2]
Included in Regulatory Assets/Liabilities										25	[3]	(27)	[3]	(30)	[3]	(31)	[3]	0	[3]	0	[3]	0	[3]	0		25	[3]	(27)	[3]	(30)	[3]	(31)	[3]	0	[3]	0	[3]			0	[3]
Purchases, (Sales)										0	[4]	10	[4]	0	[4]	29	[4]	0	[4]	10	[4]	0	[4]	29	[4]	0	[4]	0	[4]	0	[4]	0	[4]	0	[4]	0	[4]			0	[4]
Issuances (Settlements)										(9)	[5]	3	[5]	(52)	[5]	(22)	[5]	(9)	[5]	3	[5]	(52)	[5]	(22)	[5]	0	[5]	0	[5]	0	[5]	0	[5]	0	[5]	0	[5]			0	[5]
Transfers In (Out)										0	[6]	0	[6]	0	[6]	0	[6]	0	[6]	0	[6]	0	[6]	0	[6]	0	[6]	0	[6]	0	[6]	0	[6]	(8)	[6]	(8)	[6]	0	0	0	[6]	0
Closing Balance										21		4		21		4		(12)		(22)		(12)		(22)		33		26		33		26		0		0		0		0
Gains and losses attributable to changes in net derivative assets and liabilities, included in Operating Income					(1)	40	12	(28)
Gains and losses attributable to changes in net derivative assets and liabilities, included in OCI				(2)			1
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	(10)	31	(12)						(25)
Purchases	10		65
Sales		0		36
Issuances	0	5	0	25
Settlements	$ (9)	$ 8	$ (52)	$ 3

[1] PSEG’s and Power’s gains and losses attributable to changes in net derivative assets and liabilities include $(1) million and $12 million in Operating Income in 2012 and 2011, respectively, $1 million in OCI and less than $1 million in Income from Discontinued Operations in 2011. Of the $(1) million in Operating Income in 2012, $(10) million is unrealized. Of the $12 million in Operating Income in 2011, $31 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] PSEG’s and Power’s gains and losses attributable to changes in net derivative assets and liabilities include $40 million and $(28) million in Operating Income in 2012 and 2011, respectively, $(2) million in OCI and $3 million in Income from Discontinued Operations in 2011. Of the $40 million in Operating Income in 2012, $(12) million is unrealized. Of the $(28) million in Operating Income in 2011, $(25) 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.

[3] 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.

[4] Includes $10 million in purchases and $0 million in sales for the three months ended September 30, 2011. Includes $65 million in purchases and $(36) million in sales for the nine months months ended September 30, 2011.

[5] Includes $0 million and $(5) million in issuances and $(9) million and $8 million in settlements for the three months ended September 30, 2012 and 2011, respectively. Includes $0 million and $(25) million in issuances and $(52) million and $3 million in settlements for the nine months ended September 30, 2012 and 2011, respectively.

[6] There were no transfers among levels during the three months ended September 30, 2012 and 2011 and the nine months ended September 30, 2012. During the nine months ended September 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.