Supplementary Financial Information - Schedule of Other Income and Deductions (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
NDT net income (loss)	$ 100	$ 95	$ 197	$ 170
Insurance settlements	0	21	80	22
Gain on sale of land	0	5	0	6
Gain on TRA settlement	0	0	0	10
Interest income	4	9	14	50
All other	1	6	0	24
Total other income, net	$ 105	$ 136	291	$ 282
Martin Lake Incident \| ERCOT
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other income, net			$ 80

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