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REVENUE FROM CONTRACTS WITH CUSTOMERS - Performance Obligations (Details) $ in Millions | Dec. 31, 2021 USD ($)
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Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 577
Expected timing of satisfaction | 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 462
Expected timing of satisfaction | 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 341
Expected timing of satisfaction | 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 319
Expected timing of satisfaction | 1 year
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 | $ 295
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 | $ 2,309
Expected timing of satisfaction |
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 33
Expected timing of satisfaction | 1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 24
Expected timing of satisfaction | 1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 7
Expected timing of satisfaction | 1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 5
Expected timing of satisfaction | 1 year
Alabama Power | 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 | $ 0
Expected timing of satisfaction | 1 year
Alabama Power | 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 | $ 0
Expected timing of satisfaction |
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 68
Expected timing of satisfaction | 1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 48
Expected timing of satisfaction | 1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 25
Expected timing of satisfaction | 1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 22
Expected timing of satisfaction | 1 year
Georgia Power | 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 | $ 11
Expected timing of satisfaction | 1 year
Georgia Power | 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 | $ 31
Expected timing of satisfaction |
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 331
Expected timing of satisfaction | 1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 293
Expected timing of satisfaction | 1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 309
Expected timing of satisfaction | 1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 |
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] |
Revenue, remaining performance obligation | $ 292
Expected timing of satisfaction | 1 year
Southern Power | 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 | $ 287
Expected timing of satisfaction | 1 year
Southern Power | 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 | $ 2,294
Expected timing of satisfaction |

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