Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax (Changes in AOCI) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Jan. 01, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		$ 0		$ (81)	$ (176)
Beginning Balance	$ (377)	(229)	$ (263)
Other Comprehensive Income before Reclassifications	(38)	(9)	77
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	7	37	(43)
Net Current Period Other Comprehensive Income (Loss)	(31)	28	34
Ending Balance	(489)	(377)	(229)
Net Change in Accumulated Other Comprehensive Income	(112)	(148)
PSEG Power LLC
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption		0		(69)	(175)
Beginning Balance	(319)	(172)	(211)
Other Comprehensive Income before Reclassifications	(17)	(3)	78
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	4	31	(39)
Net Current Period Other Comprehensive Income (Loss)	(13)	28	39
Ending Balance	(401)	(319)	(172)
Net Change in Accumulated Other Comprehensive Income	(82)	(147)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				0	0
Beginning Balance	(1)	0	2
Other Comprehensive Income before Reclassifications	(17)	(1)	0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	3	0	(2)
Net Current Period Other Comprehensive Income (Loss)	(14)	(1)	(2)
Ending Balance	(15)	(1)	0
Net Change in Accumulated Other Comprehensive Income	(14)	(1)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member] | PSEG Power LLC
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				0	0
Beginning Balance	0	0	0
Other Comprehensive Income before Reclassifications	0	0	0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	0	0	0
Net Current Period Other Comprehensive Income (Loss)	0	0	0
Ending Balance	0	0	0
Net Change in Accumulated Other Comprehensive Income	0	0
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				(81)	0
Beginning Balance	(360)	(406)	(398)
Other Comprehensive Income before Reclassifications	(70)	17	(32)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	12	29	24
Net Current Period Other Comprehensive Income (Loss)	(58)	46	(8)
Ending Balance	(499)	(360)	(406)
Net Change in Accumulated Other Comprehensive Income	(139)	46
Accumulated Defined Benefit Plans Adjustment [Member] | PSEG Power LLC
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				(69)	0
Beginning Balance	(306)	(347)	(340)
Other Comprehensive Income before Reclassifications	(55)	16	(28)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	10	25	21
Net Current Period Other Comprehensive Income (Loss)	(45)	41	(7)
Ending Balance	(420)	(306)	(347)
Net Change in Accumulated Other Comprehensive Income	(114)	41
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				0	(176)
Beginning Balance	(16)	177	133
Other Comprehensive Income before Reclassifications	49	(25)	109
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(8)	8	(65)
Net Current Period Other Comprehensive Income (Loss)	41	(17)	44
Ending Balance	25	(16)	177
Net Change in Accumulated Other Comprehensive Income	41	(193)
Accumulated Net Unrealized Investment Gain (Loss) [Member] | PSEG Power LLC
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				$ 0	$ (175)
Beginning Balance	(13)	175	129
Other Comprehensive Income before Reclassifications	38	(19)	106
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	(6)	6	(60)
Net Current Period Other Comprehensive Income (Loss)	32	(13)	46
Ending Balance	19	(13)	$ 175
Net Change in Accumulated Other Comprehensive Income	$ 32	$ (188)