Reportable Segments - Schedule of Interest Income and Expenditures for Long-Lived Assets (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Houston Electric | ||||
| Segment Reporting Information [Line Items] | ||||
| Interest income | $ 7 | $ 7 | $ 9 | $ 11 |
| CERC | ||||
| Segment Reporting Information [Line Items] | ||||
| Interest income | $ 9 | $ 1 | $ 10 | $ 1 |