Accumulated Other Comprehensive Income (Loss), Net of Tax (Changes of AOCI) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	$ (504)	$ (489)	$ (489)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(40)	10
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	2	(2)
Other Comprehensive Income (Loss), net of tax	(38)	8
Accumulated Other Comprehensive Income (Loss), Ending Balance	(542)	(481)	(504)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(9)	(15)	(15)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	(4)	(4)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	1	1	10
Other Comprehensive Income (Loss), net of tax	1	(3)
Accumulated Other Comprehensive Income (Loss), Ending Balance	(8)	(18)	(9)
Pension and OPEB Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(545)	(499)	(499)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	3	3
Other Comprehensive Income (Loss), net of tax	3	3
Accumulated Other Comprehensive Income (Loss), Ending Balance	(542)	(496)	(545)
Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	50	25	25
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(40)	14
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(2)	(6)
Other Comprehensive Income (Loss), net of tax	(42)	8
Accumulated Other Comprehensive Income (Loss), Ending Balance	8	33	50
PSEG Power [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(419)	(401)	(401)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(31)	11
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	1	(2)
Other Comprehensive Income (Loss), net of tax	(30)	9
Accumulated Other Comprehensive Income (Loss), Ending Balance	(449)	(392)	(419)
PSEG Power [Member] | Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	0	0	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	0	0
Other Comprehensive Income (Loss), net of tax	0	0
Accumulated Other Comprehensive Income (Loss), Ending Balance	0	0	0
PSEG Power [Member] | Pension and OPEB Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(459)	(420)	(420)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	2	2
Other Comprehensive Income (Loss), net of tax	2	2
Accumulated Other Comprehensive Income (Loss), Ending Balance	(457)	(418)	(459)
PSEG Power [Member] | Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	40	19	19
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(31)	11
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(1)	(4)
Other Comprehensive Income (Loss), net of tax	(32)	7
Accumulated Other Comprehensive Income (Loss), Ending Balance	$ 8	$ 26	$ 40