Reportable Segments - Narrative (Details) - USD ($) $ in Millions |
6 Months Ended | |
|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Segment Reporting Information [Line Items] | ||
| Expenditures for Long-lived Assets | $ 2,430 | $ 1,670 |
| Houston Electric | ||
| Segment Reporting Information [Line Items] | ||
| Expenditures for Long-lived Assets | 1,200 | 846 |
| CERC | ||
| Segment Reporting Information [Line Items] | ||
| Expenditures for Long-lived Assets | $ 667 | $ 683 |