Fair Value Measurements (Schedule Of Quantitative Information About Level 3 Fair Value Measurements) (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value	$ 21		$ 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	21		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	21		10
Liabilities, Fair Value	$ 0		$ 0
Valuation Technique used	Discounted Cash flow	Discounted Cash flow
Significant Unobservable Inputs	Load Shaping Cost	Historic Load Variability
Historic Load Variability	3.00%
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	10.00%		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	$ (2)		$ (3)
Valuation Technique used	Discounted Cash flow	Discounted Cash flow
Significant Unobservable Inputs	Average Historical Basis	Average Historical Basis
Average Historical Basis	(22.00%)
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	(70.00%)		(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	0.00%		0.00%

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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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