Income Taxes (Narrative) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Federal income tax rate	21.00%
Regulatory Liabilities	$ 2,707	$ 3,002
NJ tax surcharge percent for 2020 to 2021 extended to 2023	2.50%
Tax Adjustment Credit	$ (205)	(272)	$ (30)
NJ tax surcharge percent for 2018 to 2019	1.50%
Public Service Electric and Gas Company
Income Taxes [Line Items]
Regulatory Liabilities	$ 2,707	3,002
NOL Carryforwards	29
Excess deferred income tax flowback	286
Tax Adjustment Credit	(205)	(272)	$ (30)
Excess Deferred Income Taxes excluding amounts from previously realized repair deductions [Member] | Public Service Electric and Gas Company
Income Taxes [Line Items]
Reduction in Regulatory Liability	$ 255
Reduction in Deferred Tax Liabilities		1,900
Regulatory Liabilities		$ 2,600