Financial Information By Business Segments (Financial Information By Business Segments) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Segment Reporting Information [Line Items]
Operating Revenues		$ 9,603		$ 10,076		$ 9,696
Depreciation and Amortization		1,285		1,248		1,158
Operating Income (Loss)		2,270		1,943		2,298
Income from Equity Method Investments		14		14		15
Interest Income		25		26		29
Interest Expense		(600)		(569)		(476)
Income (Loss) before Income Taxes		2,301		1,950		1,855
Income Tax Expense (Benefit)		396		257		417
Net Income (Loss)		1,905	[1]	1,693	[1]	1,438
Gross Additions to Long-Lived Assets		2,923		3,166		3,912
Total Assets		50,050		47,730		45,326
Investments in Equity Method Subsidiaries		64		67		86
PSEG Power LLC
Segment Reporting Information [Line Items]
Operating Revenues		3,634		4,385		4,146
Gain (loss) on sale, net of tax		(86)		286
Public Service Electric and Gas Company
Segment Reporting Information [Line Items]
Operating Revenues		6,608		6,625		6,471
Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues		595		549		571
Retained Earnings [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)		1,905		1,693		1,438
Operating Segments [Member] | PSEG Power LLC
Segment Reporting Information [Line Items]
Operating Revenues		3,634		4,385		4,146
Depreciation and Amortization		368		377		354
Operating Income (Loss)		603		448		596
Income from Equity Method Investments		14		14		15
Interest Income		6		7		5
Interest Expense		(121)		(119)		(76)
Income (Loss) before Income Taxes		782		671		431
Income Tax Expense (Benefit)		188		203		66
Net Income (Loss)		594	[1]	468	[1]	365
Gross Additions to Long-Lived Assets		404		607		996
Total Assets		12,704		12,805		12,594
Investments in Equity Method Subsidiaries		64		66		86
Operating Segments [Member] | Public Service Electric and Gas Company
Segment Reporting Information [Line Items]
Operating Revenues		6,608		6,625		6,471
Depreciation and Amortization		887		837		770
Operating Income (Loss)		1,639		1,469		1,606
Income from Equity Method Investments		0		0		0
Interest Income		17		18		21
Interest Expense		(388)		(361)		(333)
Income (Loss) before Income Taxes		1,567		1,343		1,411
Income Tax Expense (Benefit)		240		93		344
Net Income (Loss)		1,327		1,250		1,067
Gross Additions to Long-Lived Assets		2,507		2,542		2,896
Total Assets		35,581		33,266		31,109
Investments in Equity Method Subsidiaries		0		0		0
Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Operating Revenues	[2]	595		549		571
Depreciation and Amortization	[2]	30		34		34
Operating Income (Loss)	[2]	28		26		96
Income from Equity Method Investments	[2]	0		0		0
Interest Income	[2]	5		6		9
Interest Expense	[2]	(94)		(94)		(73)
Income (Loss) before Income Taxes	[2]	(48)		(64)		13
Income Tax Expense (Benefit)	[2]	(32)		(39)		7
Net Income (Loss)	[2]	(16)		(25)		6
Gross Additions to Long-Lived Assets	[2]	12		17		20
Total Assets	[2]	2,692		2,715		2,604
Investments in Equity Method Subsidiaries	[2]	0		1		0
Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	[3]	(1,234)		(1,483)		(1,492)
Depreciation and Amortization	[3]	0		0		0
Operating Income (Loss)	[3]	0		0		0
Income from Equity Method Investments	[3]	0		0		0
Interest Income	[3]	(3)		(5)		(6)
Interest Expense	[3]	3		5		6
Income (Loss) before Income Taxes	[3]	0		0		0
Income Tax Expense (Benefit)	[3]	0		0		0
Net Income (Loss)	[3]	0				0
Gross Additions to Long-Lived Assets	[3]	0		0		0
Total Assets	[3]	(927)		(1,056)		(981)
Investments in Equity Method Subsidiaries	[3]	0		0		0
PSEG Power LLC
Segment Reporting Information [Line Items]
Operating Revenues		3,634		4,385		4,146
Depreciation and Amortization		368		377		354
Operating Income (Loss)		603		448		596
Income from Equity Method Investments		14		14		15
Interest Expense		(121)		(119)		(76)
Income (Loss) before Income Taxes		782		671		431
Income Tax Expense (Benefit)		188		203		66
Net Income (Loss)		594		468		365
Total Assets		12,704		12,805
PSEG Power LLC | Retained Earnings [Member]
Segment Reporting Information [Line Items]
Net Income (Loss)		$ 594		$ 468		$ 365

[1] Includes an after-tax gain of $86 million in the year ended December 31, 2020 related to the sale of PSEG Power’s interest in the Yards Creek generation facility and an after-tax loss of $286 million in the year ended December 31, 2019 related to the sale of PSEG Power’s ownership interests in the Keystone and Conemaugh fossil generation plants. See Note 4. Early Plant Retirements/Asset Dispositions for additional information.

[2] Includes amounts applicable to Energy Holdings and PSEG LI, which are below the quantitative threshold for separate disclosure as reportable segments. Other also includes amounts applicable to PSEG (parent corporation) and Services.

[3] Intercompany eliminations primarily relate to intercompany transactions between PSE&G and PSEG Power. For a further discussion of the intercompany transactions between PSE&G and PSEG Power, see Note 26. Related-Party Transactions.