XML 95 R64.htm IDEA: XBRL DOCUMENT
v3.25.3

Regulatory Matters (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2025
Regulated Operations [Abstract] |
Schedule of Cost Recovery Clauses | The fuel and natural gas cost recovery balances for the traditional electric operating companies and Southern Company Gas, respectively, at September 30, 2025 and December 31, 2024 were as follows:
Regulatory Clause | Balance Sheet Line Item | At September 30, 2025 | At December 31, 2024
|  | (in millions)
Alabama Power |  |  |
Rate ECR | Other regulatory assets, current | $ | 14 |  | $ | — |
| Other regulatory assets, deferred | 69 |  | — |
| Other regulatory liabilities, current | — |  | 29 |
Georgia Power |  |  |
Fuel Cost Recovery | Receivables – under recovered retail fuel clause revenues | $ | 487 |  | $ | 713 |
| Deferred under recovered retail fuel clause revenues | 197 |  | 453 |
Mississippi Power |  |  |
Fuel Cost Recovery(*) | Receivables – customer accounts, net | $ | 30 |  | $ | — |
| Deferred under recovered retail fuel clause revenues | — |  | 32 |
| Over recovered retail fuel clause revenues | — |  | 32 |
Southern Company Gas |  |  |
Natural Gas Cost Recovery | Natural gas cost over recovery | $ | 163 |  | $ | 193 |
(*)Mississippi Power also has wholesale MRA and Market Based (MB) fuel cost recovery factors. At September 30, 2025 and December 31, 2024, wholesale MRA fuel cost over recovery was immaterial and $19 million, respectively, and was included in other current liabilities on Mississippi Power's balance sheets. The wholesale MB fuel cost recovery was immaterial for both periods presented.
Schedule of Construction Projects |
Project(*) | Resource | Approximate Nameplate Capacity (MW) | Projected COD | Regulatory Approval
Projects Under Construction at September 30, 2025
McGrau Ford | Battery energy storage | 265 | Fourth quarter 2026 | 2022 IRP
Plant Yates Units 8 through 10 | Combustion turbine | 1,326 | Fourth quarter 2026 through third quarter 2027 | 2023 IRP Update
Various facilities | Battery energy storage | 500 | Second quarter 2026 through fourth quarter 2026 | 2023 IRP Update
(*)Excludes a 200-MW battery energy storage facility which has not incurred significant costs. See "Integrated Resource Plans" herein for additional information.

X
- Definition [Table Text Block] for Cost Recovery Clauses [Table] + References No definition available. + Details
Name: | so_CostRecoveryClausesTableTextBlock
Namespace Prefix: | so_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition [Table Text Block] for Schedule of Construction Projects [Table] + References No definition available. + Details
Name: | so_ScheduleofConstructionProjectsTableTextBlock
Namespace Prefix: | so_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_RegulatedOperationsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration