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Revenue from Contracts with Customers and Lease Income - Schedule of Remaining Performance Obligations (Details) $ in Millions | Sep. 30, 2025 USD ($)
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Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-10-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 296
Performance obligation, expected timing of satisfaction | 3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 742
Performance obligation, expected timing of satisfaction | 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 470
Performance obligation, expected timing of satisfaction | 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 344
Performance obligation, expected timing of satisfaction | 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 309
Performance obligation, expected timing of satisfaction | 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 2,636
Performance obligation, expected timing of satisfaction |
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-10-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 46
Performance obligation, expected timing of satisfaction | 3 months
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 6
Performance obligation, expected timing of satisfaction | 1 year
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 5
Performance obligation, expected timing of satisfaction | 1 year
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 2
Performance obligation, expected timing of satisfaction | 1 year
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 0
Performance obligation, expected timing of satisfaction | 1 year
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 0
Performance obligation, expected timing of satisfaction |
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-10-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 19
Performance obligation, expected timing of satisfaction | 3 months
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 48
Performance obligation, expected timing of satisfaction | 1 year
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 22
Performance obligation, expected timing of satisfaction | 1 year
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 15
Performance obligation, expected timing of satisfaction | 1 year
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 2
Performance obligation, expected timing of satisfaction | 1 year
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 27
Performance obligation, expected timing of satisfaction |
MISSISSIPPI POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-10-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 16
Performance obligation, expected timing of satisfaction | 3 months
MISSISSIPPI POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 66
Performance obligation, expected timing of satisfaction | 1 year
MISSISSIPPI POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 69
Performance obligation, expected timing of satisfaction | 1 year
MISSISSIPPI POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 73
Performance obligation, expected timing of satisfaction | 1 year
MISSISSIPPI POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 12
Performance obligation, expected timing of satisfaction | 1 year
MISSISSIPPI POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 0
Performance obligation, expected timing of satisfaction |
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-10-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 75
Performance obligation, expected timing of satisfaction | 3 months
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 331
Performance obligation, expected timing of satisfaction | 1 year
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 340
Performance obligation, expected timing of satisfaction | 1 year
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 316
Performance obligation, expected timing of satisfaction | 1 year
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 312
Performance obligation, expected timing of satisfaction | 1 year
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2030-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 2,609
Performance obligation, expected timing of satisfaction |

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