Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Operating revenues	$ 3,933	$ 3,054
Fuel, purchased power costs, and delivery fees	(2,447)	(1,716)
Operating costs	(693)	(498)
Selling, general, and administrative expenses	(391)	(351)
Depreciation and amortization	(522)	(403)
Interest expenses and related charges	(319)	(170)
Income tax benefit	176	20
Other	(5)	82
Net income (loss)	(268)	18
Capital expenditures, including nuclear fuel and excluding growth expenditures	729	421
Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	4,919	4,094
Fuel, purchased power costs, and delivery fees	(3,433)	(2,756)
Operating costs	(693)	(497)
Selling, general, and administrative expenses	(361)	(302)
Depreciation and amortization	(503)	(388)
Interest expenses and related charges	8	2
Income tax benefit	0	0
Other	(6)	42
Net income (loss)	(69)	195
Capital expenditures, including nuclear fuel and excluding growth expenditures	716	410
Corporate and Other
Segment Reporting Information [Line Items]
Operating revenues	(986)	(1,040)
Fuel, purchased power costs, and delivery fees	986	1,040
Operating costs	0	(1)
Selling, general, and administrative expenses	(30)	(49)
Depreciation and amortization	(19)	(15)
Interest expenses and related charges	(327)	(172)
Income tax benefit	176	20
Other	1	40
Net income (loss)	(199)	(177)
Capital expenditures, including nuclear fuel and excluding growth expenditures	13	11
Retail | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	3,168	2,494
Fuel, purchased power costs, and delivery fees	(1,712)	(1,647)
Operating costs	(40)	(31)
Selling, general, and administrative expenses	(243)	(225)
Depreciation and amortization	(23)	(23)
Interest expenses and related charges	(18)	(6)
Income tax benefit	0	0
Other	0	(1)
Net income (loss)	1,132	561
Capital expenditures, including nuclear fuel and excluding growth expenditures	3	0
Texas | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	210	459
Fuel, purchased power costs, and delivery fees	(497)	(381)
Operating costs	(258)	(257)
Selling, general, and administrative expenses	(41)	(35)
Depreciation and amortization	(150)	(134)
Interest expenses and related charges	14	10
Income tax benefit	0	0
Other	2	2
Net income (loss)	(720)	(336)
Capital expenditures, including nuclear fuel and excluding growth expenditures	419	316
East | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	1,380	856
Fuel, purchased power costs, and delivery fees	(1,172)	(647)
Operating costs	(327)	(181)
Selling, general, and administrative expenses	(58)	(28)
Depreciation and amortization	(316)	(210)
Interest expenses and related charges	12	(1)
Income tax benefit	0	0
Other	(9)	38
Net income (loss)	(490)	(173)
Capital expenditures, including nuclear fuel and excluding growth expenditures	264	88
West | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	157	276
Fuel, purchased power costs, and delivery fees	(52)	(79)
Operating costs	(12)	(11)
Selling, general, and administrative expenses	(2)	(4)
Depreciation and amortization	(15)	(14)
Interest expenses and related charges	1	0
Income tax benefit	0	0
Other	0	0
Net income (loss)	77	168
Capital expenditures, including nuclear fuel and excluding growth expenditures	30	6
Asset Closure | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	4	9
Fuel, purchased power costs, and delivery fees	0	(2)
Operating costs	(56)	(17)
Selling, general, and administrative expenses	(17)	(10)
Depreciation and amortization	1	(7)
Interest expenses and related charges	(1)	(1)
Income tax benefit	0	0
Other	1	3
Net income (loss)	(68)	(25)
Capital expenditures, including nuclear fuel and excluding growth expenditures	$ 0	$ 0