Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
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-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14557-108349

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=121555522&loc=d3e12021-110248

Name:	us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Commitments And Contingent Liabilities (Litigation) (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Jan. 31, 2021
LIPA complaint \| Maximum [Member]
Loss Contingencies [Line Items]
Sewaren 7 Construction complaint amount	$ 70.0
LIPA complaint \| Minimum [Member]
Loss Contingencies [Line Items]
Sewaren 7 Construction complaint amount	7.0
PSEG Power [Member] \| Sewaren 7 Litigation [Member]
Loss Contingencies [Line Items]
Original Claim Amount	$ 93.0
PSEG Power [Member] \| Sewaren 7 Litigation [Member] \| Maximum [Member]
Loss Contingencies [Line Items]
Sewaren 7 Construction complaint amount		$ 68.0