Accumulated Other Comprehensive Income (Loss), Net of Tax (Changes of AOCI) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect Adjustment					$ (2)	$ 81
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	$ (455)	$ (432)	$ (489)	$ (377)	(377)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	3	(7)	43	14
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	0	1	(6)	6
Other Comprehensive Income (Loss), net of tax	3	(6)	37	20
Accumulated Other Comprehensive Income (Loss), Ending Balance	(452)	(438)	(452)	(438)	(489)
Net Change in Accumulated Other Comprehensive Income				(61)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect Adjustment						0
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(15)	(18)	(15)	(1)	(1)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0	(4)	(17)	(17)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	4	1	8	1	3
Other Comprehensive Income (Loss), net of tax	4	1	4	(16)
Accumulated Other Comprehensive Income (Loss), Ending Balance	(11)	(17)	(11)	(17)	(15)
Net Change in Accumulated Other Comprehensive Income				(16)
Pension and OPEB Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect Adjustment						81
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(493)	(437)	(499)	(360)	(360)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	(20)	0	(23)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	3	3	9	10
Other Comprehensive Income (Loss), net of tax	3	(17)	9	(13)
Accumulated Other Comprehensive Income (Loss), Ending Balance	(490)	(454)	(490)	(454)	(499)
Net Change in Accumulated Other Comprehensive Income				(94)
Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect Adjustment						0
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	53	23	25	(16)	(16)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	3	13	47	54
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(7)	(3)	(23)	(5)
Other Comprehensive Income (Loss), net of tax	(4)	10	24	49
Accumulated Other Comprehensive Income (Loss), Ending Balance	49	33	49	33	25
Net Change in Accumulated Other Comprehensive Income				49
PSEG Power [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect Adjustment						69	$ 0
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(374)	(354)	(401)	(319)	(319)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	3	(4)	38	25
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(3)	(1)	(11)	4
Other Comprehensive Income (Loss), net of tax	0	(5)	27	29
Accumulated Other Comprehensive Income (Loss), Ending Balance	(374)	(359)	(374)	(359)	(401)
Net Change in Accumulated Other Comprehensive Income				(40)
PSEG Power [Member] | Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect Adjustment						0
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	0	0	0	0	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0	0	0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	0	0	0	0
Other Comprehensive Income (Loss), net of tax	0	0	0	0
Accumulated Other Comprehensive Income (Loss), Ending Balance	0	0	0	0	0
Net Change in Accumulated Other Comprehensive Income				0
PSEG Power [Member] | Pension and OPEB Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect Adjustment						69
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(415)	(372)	(420)	(306)	(306)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	(14)	0	(17)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	2	2	7	8
Other Comprehensive Income (Loss), net of tax	2	(12)	7	(9)
Accumulated Other Comprehensive Income (Loss), Ending Balance	(413)	(384)	(413)	(384)	(420)
Net Change in Accumulated Other Comprehensive Income				(78)
PSEG Power [Member] | Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect Adjustment						$ 0
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	41	18	19	(13)	(13)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	3	10	38	42
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(5)	(3)	(18)	(4)
Other Comprehensive Income (Loss), net of tax	(2)	7	20	38
Accumulated Other Comprehensive Income (Loss), Ending Balance	$ 39	$ 25	$ 39	25	$ 19
Net Change in Accumulated Other Comprehensive Income				$ 38