Regulatory Matters - Schedule of Allowed Equity Return (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Sep. 30, 2025 |
Sep. 30, 2024 |
Sep. 30, 2025 |
Sep. 30, 2024 |
Dec. 31, 2024 |
|
| Public Utilities, General Disclosures [Line Items] | |||||
| Unrecognized equity return | $ 313 | $ 313 | $ 251 | ||
| Allowed equity return recognized | 9 | $ 1 | 18 | $ 22 | |
| Houston Electric | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Unrecognized equity return | 144 | 144 | 94 | ||
| Allowed equity return recognized | 8 | 0 | 14 | 19 | |
| CERC | |||||
| Public Utilities, General Disclosures [Line Items] | |||||
| Unrecognized equity return | 105 | 105 | $ 92 | ||
| Allowed equity return recognized | $ 1 | $ 1 | $ 3 | $ 2 | |