Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting Information [Line Items]
Operating revenues	$ 4,971			$ 6,288			$ 13,154	$ 13,187
Fuel, purchased power costs, and delivery fees	(2,370)			(2,207)			(6,791)	(5,520)
Operating costs	(655)			(616)			(2,081)	(1,742)
Selling, general, and administrative expenses	(444)			(411)			(1,254)	(1,137)
Depreciation and amortization	(460)			(466)			(1,523)	(1,306)
Interest expenses and related charges	(286)			(332)			(908)	(743)
Income tax expense	(204)			(555)			(104)	(694)
Other	100			136			218	277
Net income	652	$ 327	$ (268)	1,837	$ 467	$ 18	711	2,322
Capital expenditures, including nuclear fuel and excluding growth expenditures							1,696	1,471
Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	7,855			10,591			19,619	19,808
Fuel, purchased power costs, and delivery fees	(5,257)			(6,510)			(13,260)	(12,142)
Operating costs	(662)			(615)			(2,087)	(1,740)
Selling, general, and administrative expenses	(385)			(355)			(1,129)	(972)
Depreciation and amortization	(441)			(449)			(1,466)	(1,256)
Interest expenses and related charges	8			(1)			25	(3)
Income tax expense	0			0			(1)	0
Other	98			128			213	219
Net income	1,216			2,789			1,914	3,914
Capital expenditures, including nuclear fuel and excluding growth expenditures							1,285	985
Corporate and Other
Segment Reporting Information [Line Items]
Operating revenues	(2,884)			(4,303)			(6,465)	(6,621)
Fuel, purchased power costs, and delivery fees	2,887			4,303			6,469	6,622
Operating costs	7			(1)			6	(2)
Selling, general, and administrative expenses	(59)			(56)			(125)	(165)
Depreciation and amortization	(19)			(17)			(57)	(50)
Interest expenses and related charges	(294)			(331)			(933)	(740)
Income tax expense	(204)			(555)			(103)	(694)
Other	2			8			5	58
Net income	(564)			(952)			(1,203)	(1,592)
Capital expenditures, including nuclear fuel and excluding growth expenditures							411	486
Corporate and Other | Nuclear fuel
Segment Reporting Information [Line Items]
Capital expenditures, including nuclear fuel and excluding growth expenditures							380	445
Retail | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	4,139			4,251			10,839	9,913
Fuel, purchased power costs, and delivery fees	(3,815)			(5,117)			(8,848)	(8,724)
Operating costs	(54)			(47)			(131)	(118)
Selling, general, and administrative expenses	(270)			(266)			(769)	(715)
Depreciation and amortization	(23)			(31)			(70)	(85)
Interest expenses and related charges	(18)			(16)			(53)	(38)
Income tax expense	0			0			0	0
Other	1			0			1	(1)
Net income	(40)			(1,226)			969	232
Capital expenditures, including nuclear fuel and excluding growth expenditures							10	3
Texas
Segment Reporting Information [Line Items]
Amortization of nuclear fuel	35			28			96	80
Texas | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	1,799			4,244			3,797	4,924
Fuel, purchased power costs, and delivery fees	(544)			(487)			(1,509)	(1,249)
Operating costs	(243)			(242)			(778)	(753)
Selling, general, and administrative expenses	(38)			(40)			(122)	(116)
Depreciation and amortization	(160)			(155)			(477)	(423)
Interest expenses and related charges	9			11			41	33
Income tax expense	0			0			0	0
Other	0			23			14	29
Net income	823			3,354			966	2,445
Capital expenditures, including nuclear fuel and excluding growth expenditures							714	544
East
Segment Reporting Information [Line Items]
Amortization of nuclear fuel	94			95			270	189
East | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	1,750			1,853			4,610	4,241
Fuel, purchased power costs, and delivery fees	(866)			(859)			(2,784)	(2,000)
Operating costs	(338)			(296)			(1,020)	(774)
Selling, general, and administrative expenses	(59)			(32)			(175)	(93)
Depreciation and amortization	(244)			(241)			(876)	(684)
Interest expenses and related charges	16			4			36	4
Income tax expense	0			0			(1)	0
Other	95			97			194	177
Net income	354			526			(16)	871
Capital expenditures, including nuclear fuel and excluding growth expenditures							444	393
West | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	165			232			347	701
Fuel, purchased power costs, and delivery fees	(32)			(45)			(119)	(164)
Operating costs	(15)			(11)			(45)	(39)
Selling, general, and administrative expenses	(2)			(8)			(11)	(14)
Depreciation and amortization	(14)			(15)			(45)	(43)
Interest expenses and related charges	2			1			4	1
Income tax expense	0			0			0	0
Other	1			1			1	0
Net income	105			155			132	442
Capital expenditures, including nuclear fuel and excluding growth expenditures							117	44
Asset Closure | Operating Segments
Segment Reporting Information [Line Items]
Operating revenues	2			11			26	29
Fuel, purchased power costs, and delivery fees	0			(2)			0	(5)
Operating costs	(12)			(19)			(113)	(56)
Selling, general, and administrative expenses	(16)			(9)			(52)	(34)
Depreciation and amortization	0			(7)			2	(21)
Interest expenses and related charges	(1)			(1)			(3)	(3)
Income tax expense	0			0			0	0
Other	1			7			3	14
Net income	$ (26)			$ (20)			(137)	(76)
Capital expenditures, including nuclear fuel and excluding growth expenditures							$ 0	$ 1