Fair Value of Financial Instruments - Schedule of Estimated Carrying Values and Fair Values (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
| Long-term debt, including current portion — affiliate | $ 9,141 | $ 8,680 |
| Carrying Amount | ||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
| Long-term debt, including current portion — affiliate | 4 | 6 |
| Long-term debt, including current portion — external | 9,141 | 8,676 |
| Fair Value | ||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | ||
| Long-term debt, including current portion — affiliate | 4 | 6 |
| Long-term debt, including current portion — external | $ 8,787 | $ 8,382 |