Fair Value Measurements (Schedule Of Quantitative Information About Level 3 Fair Value Measurements) (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 2		$ 10
Liabilities, Fair Value	(2)		(3)
PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	2		10
Liabilities, Fair Value	(2)		(3)
Electric Load Contracts [Member] \| PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	2		10
Liabilities, Fair Value	$ (1)		$ 0
Valuation Technique used	Discounted Cash flow	Discounted Cash flow
Significant Unobservable Inputs	Load Shaping Cost	Historic Load Variability
Historic Load Variability	4.00%
Electric Load Contracts [Member] \| Minimum [Member] \| PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Historic Load Variability	0.00%		0.00%
Electric Load Contracts [Member] \| Maximum [Member] \| PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Historic Load Variability	12.00%		10.00%
Gas Physical Contract [Member] \| PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 0		$ 0
Liabilities, Fair Value	$ (1)		$ (3)
Valuation Technique used	Discounted Cash flow	Discounted Cash flow
Significant Unobservable Inputs	Historical Basis Adjustment	Average Historical Basis
Average Historical Basis	(31.00%)
Gas Physical Contract [Member] \| Minimum [Member] \| PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Average Historical Basis	(50.00%)		(50.00%)
Gas Physical Contract [Member] \| Maximum [Member] \| PSEG Power [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Average Historical Basis	(20.00%)		0.00%

Average Historical Basis

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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- Definition

Fair value of financial and nonfinancial obligations.

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