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LEASES - Major Categories of Lease Obligations (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Lessee, Lease, Description [Line Items] |  |
Lease obligations | $ 1,969 | $ 2,083
Alabama Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 124 | 175
Georgia Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 1,291 | 1,452
Mississippi Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 28 | 28
Southern Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 526 | 451
Southern Company Gas |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 70 | 82
Electric generating units |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 802 | 941
Electric generating units | Alabama Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 104 | 146
Electric generating units | Georgia Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 1,217 | 1,368
Electric generating units | Mississippi Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 0 | 0
Electric generating units | Southern Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 0 | 0
Electric generating units | Southern Company Gas |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 0 | 0
Real estate/land |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 876 | 815
Real estate/land | Alabama Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 3 | 4
Real estate/land | Georgia Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 49 | 53
Real estate/land | Mississippi Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 2 | 2
Real estate/land | Southern Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 526 | 451
Real estate/land | Southern Company Gas |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 45 | 61
Communication towers |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 156 | 158
Communication towers | Alabama Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 2 | 2
Communication towers | Georgia Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 4 | 3
Communication towers | Mississippi Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 0 | 0
Communication towers | Southern Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 0 | 0
Communication towers | Southern Company Gas |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 24 | 20
Railcars |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 32 | 42
Railcars | Alabama Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 10 | 16
Railcars | Georgia Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 20 | 23
Railcars | Mississippi Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 2 | 3
Railcars | Southern Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 0 | 0
Railcars | Southern Company Gas |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 0 | 0
Other |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 103 | 127
Other | Alabama Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 5 | 7
Other | Georgia Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 1 | 5
Other | Mississippi Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 24 | 23
Other | Southern Power |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | 0 | 0
Other | Southern Company Gas |  |
Lessee, Lease, Description [Line Items] |  |
Lease obligations | $ 1 | $ 1

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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