Supplementary Financial Information - Schedule of Other Noncurrent Liabilities and Deferred Credits (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Retirement and other employee benefits	$ 200	$ 224
Identifiable intangible liabilities	141	155
Regulatory liability	691	452
Operating lease liabilities	72	98
Finance lease liabilities	217	218
Liability for third-party remediation	8	8
Accrued severance costs	34	36
Tax Receivable Agreement obligation	9	14
Other accrued expenses	82	65
Total other noncurrent liabilities and deferred credits	1,454	1,270
Nuclear Plant Decommissioning - Other Noncurrent Liabilities | Comanche Peak Nuclear Power Plant
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Regulatory liability	$ 691	$ 452