Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Operating revenues	$ 4,250		$ 3,845		$ 8,183	$ 6,899
Fuel, purchased power costs, and delivery fees	(1,974)		(1,597)		(4,421)	(3,313)
Operating costs	(733)		(628)		(1,426)	(1,126)
Selling, general, and administrative expenses	(419)		(375)		(810)	(726)
Depreciation and amortization	(541)		(437)		(1,063)	(840)
Interest expenses and related charges	(303)		(241)		(622)	(411)
Income tax (expense) benefit	(76)		(159)		100	(139)
Other	123		59		118	141
Net income	327	$ (268)	467	$ 18	59	485
Capital expenditures, including nuclear fuel and excluding growth expenditures					1,348	877
Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	6,845		5,123		11,764	9,217
Fuel, purchased power costs, and delivery fees	(4,570)		(2,876)		(8,003)	(5,632)
Operating costs	(732)		(628)		(1,425)	(1,125)
Selling, general, and administrative expenses	(383)		(315)		(744)	(617)
Depreciation and amortization	(522)		(419)		(1,025)	(807)
Interest expenses and related charges	9		(4)		17	(2)
Income tax (expense) benefit	(1)		0		(1)	0
Other	121		49		115	91
Net income	767		930		698	1,125
Capital expenditures, including nuclear fuel and excluding growth expenditures					957	556
Corporate and Other
Segment Reporting Information [Line Items]
Operating revenues	(2,595)		(1,278)		(3,581)	(2,318)
Fuel, purchased power costs, and delivery fees	2,596		1,279		3,582	2,319
Operating costs	(1)		0		(1)	(1)
Selling, general, and administrative expenses	(36)		(60)		(66)	(109)
Depreciation and amortization	(19)		(18)		(38)	(33)
Interest expenses and related charges	(312)		(237)		(639)	(409)
Income tax (expense) benefit	(75)		(159)		101	(139)
Other	2		10		3	50
Net income	(440)		(463)		(639)	(640)
Capital expenditures, including nuclear fuel and excluding growth expenditures					391	321
Corporate and Other | Nuclear fuel
Segment Reporting Information [Line Items]
Capital expenditures, including nuclear fuel and excluding growth expenditures					359	295
Retail | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	3,532		3,168		6,700	5,662
Fuel, purchased power costs, and delivery fees	(3,321)		(1,960)		(5,033)	(3,607)
Operating costs	(37)		(40)		(77)	(71)
Selling, general, and administrative expenses	(256)		(224)		(499)	(449)
Depreciation and amortization	(24)		(31)		(47)	(54)
Interest expenses and related charges	(17)		(16)		(35)	(22)
Income tax (expense) benefit	0		0		0	0
Other	0		0		0	(1)
Net income	(123)		897		1,009	1,458
Capital expenditures, including nuclear fuel and excluding growth expenditures					8	0
Texas | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	1,788		221		1,998	680
Fuel, purchased power costs, and delivery fees	(468)		(381)		(965)	(762)
Operating costs	(277)		(254)		(535)	(511)
Selling, general, and administrative expenses	(43)		(41)		(84)	(76)
Depreciation and amortization	(167)		(134)		(317)	(268)
Interest expenses and related charges	18		12		32	22
Income tax (expense) benefit	0		0		0	0
Other	12		4		14	6
Net income	863		(573)		143	(909)
Capital expenditures, including nuclear fuel and excluding growth expenditures					577	271
East | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	1,480		1,532		2,860	2,388
Fuel, purchased power costs, and delivery fees	(746)		(494)		(1,918)	(1,141)
Operating costs	(355)		(297)		(682)	(478)
Selling, general, and administrative expenses	(58)		(33)		(116)	(61)
Depreciation and amortization	(316)		(233)		(632)	(443)
Interest expenses and related charges	8		1		20	0
Income tax (expense) benefit	(1)		0		(1)	0
Other	108		42		99	80
Net income	120		518		(370)	345
Capital expenditures, including nuclear fuel and excluding growth expenditures					303	250
West | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	25		193		182	469
Fuel, purchased power costs, and delivery fees	(35)		(40)		(87)	(119)
Operating costs	(18)		(17)		(30)	(28)
Selling, general, and administrative expenses	(7)		(2)		(9)	(6)
Depreciation and amortization	(16)		(14)		(31)	(28)
Interest expenses and related charges	1		0		2	0
Income tax (expense) benefit	0		0		0	0
Other	0		(1)		0	(1)
Net income	(50)		119		27	287
Capital expenditures, including nuclear fuel and excluding growth expenditures					69	34
Asset Closure | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	20		9		24	18
Fuel, purchased power costs, and delivery fees	0		(1)		0	(3)
Operating costs	(45)		(20)		(101)	(37)
Selling, general, and administrative expenses	(19)		(15)		(36)	(25)
Depreciation and amortization	1		(7)		2	(14)
Interest expenses and related charges	(1)		(1)		(2)	(2)
Income tax (expense) benefit	0		0		0	0
Other	1		4		2	7
Net income	$ (43)		$ (31)		(111)	(56)
Capital expenditures, including nuclear fuel and excluding growth expenditures					$ 0	$ 1