FINANCING ACTIVITIES - Schedule of Accounts Receivable and Accrued Unbilled Revenues (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| APPALACHIAN POWER COMPANY | ||
| Short-Term Debt [Line Items] | ||
| Accounts receivable and accrued unbilled revenues | $ 193 | $ 203 |
| INDIANA MICHIGAN POWER COMPANY | ||
| Short-Term Debt [Line Items] | ||
| Accounts receivable and accrued unbilled revenues | 179 | 175 |
| OHIO POWER COMPANY | ||
| Short-Term Debt [Line Items] | ||
| Accounts receivable and accrued unbilled revenues | 553 | 501 |
| PUBLIC SERVICE COMPANY OF OKLAHOMA | ||
| Short-Term Debt [Line Items] | ||
| Accounts receivable and accrued unbilled revenues | 182 | 140 |
| SOUTHWESTERN ELECTRIC POWER COMPANY | ||
| Short-Term Debt [Line Items] | ||
| Accounts receivable and accrued unbilled revenues | $ 197 | $ 169 |