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REGULATORY MATTERS - GPC Nuclear Construction (Details) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2021 USD ($) | Sep. 30, 2021 USD ($) | Jun. 30, 2021 USD ($) | Mar. 31, 2021 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2012 utility MW
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Estimated loss on Plant Vogtle Units 3 and 4 |  |  |  |  | $ 1,692 |  | $ 0 |
Georgia Power |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Number of construction units approved | utility |  |  |  |  |  |  |  | 2
Electric generating capacity (in MWs) | MW |  |  |  |  |  |  |  | 1,100
Estimated loss on Plant Vogtle Units 3 and 4 | $ 480 | $ 264 | $ 460 | $ 48 | $ 1,692 | $ 325 | $ 0 |
Estimated loss on Plant Vogtle Units 3 and 4, net of tax | 358 | $ 197 | $ 343 | $ 36 |  |  |  |
Pre-tax charge to income | 440 |  |  |  |  |  |  |
After tax charge to income | $ 328 |  |  |  |  |  |  |
Plant Vogtle Units 3 and 4 | Georgia Power |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Percent ownership | 45.70% |  |  |  | 45.70% |  |  |
Estimated construction financing costs | $ 3,400 |  |  |  | $ 3,400 |  |  |
Construction financing costs incurred to date | 2,900 |  |  |  | 2,900 |  |  |
Estimated cost to complete, construction contingency estimate and additional costs | 1,300 |  |  |  | 1,300 |  |  |
Estimated cost to complete, additional construction contingency estimate | 99 |  |  |  | $ 99 |  |  |
Plant Vogtle Units 3 and 4 | Georgia Power | Minimum | COVID-19 |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Estimated months of productivity loss |  |  |  |  | 3 months |  |  |
Construction financing costs | 160 |  |  |  | $ 160 |  |  |
Plant Vogtle Units 3 and 4 | Georgia Power | Maximum | COVID-19 |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Estimated months of productivity loss |  |  |  |  | 4 months |  |  |
Construction financing costs | $ 200 |  |  |  | $ 200 |  |  |
Plant Vogtle Units 3 and 4 | Georgia Power | Vogtle Owners |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Period of notice required in the event letters of credit are not renewed |  |  |  |  | 30 days |  |  |
Plant Vogtle Unit 3 | Georgia Power |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Additional base capital costs per month (up to) |  |  |  |  | $ 60 |  |  |
Plant Watson Unit 4 | Georgia Power |  |  |  |  |  |  |  |
Public Utilities, General Disclosures [Line Items] |  |  |  |  |  |  |  |
Additional base capital costs per month (up to) |  |  |  |  | $ 40 |  |  |

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