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PROPERTY, PLANT, AND EQUIPMENT - Deferred Cloud Implementation Costs (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | $ 17,259 | $ 16,298
Deferred Cloud Implementation Costs |  |
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | 240 | 162
Alabama Power |  |
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | 4,549 | 4,262
Alabama Power | Deferred Cloud Implementation Costs |  |
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | 54 | 38
Georgia Power |  |
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | 8,823 | 8,297
Georgia Power | Deferred Cloud Implementation Costs |  |
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | 81 | 58
Mississippi Power |  |
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | 877 | 805
Mississippi Power | Deferred Cloud Implementation Costs |  |
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | 11 | 7
Southern Power |  |
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | 967 | 1,150
Southern Power | Deferred Cloud Implementation Costs |  |
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | 14 | 9
Southern Company Gas |  |
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | 1,064 | 931
Southern Company Gas | Deferred Cloud Implementation Costs |  |
Property, Plant and Equipment [Line Items] |  |
Deferred cloud implementation costs | $ 35 | $ 17

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- Definition Sum of the carrying amounts as of the balance sheet date of all assets, excluding Property, Plant, and Equipment and Other Property and Investments, that are expected to be realized in cash, sold or consumed after one year or beyond the normal operating cycle, if longer. + References No definition available. + Details
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