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LEASES - Lease Costs (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Lease cost |  |  |
Operating lease cost | $ 252 | $ 297 | $ 313
Finance lease cost: |  |  |
Amortization of ROU assets | 24 | 23 | 21
Interest on lease obligations | 14 | 13 | 11
Total finance lease cost | 38 | 36 | 32
Short-term lease costs | 40 | 64 | 48
Variable lease cost | 47 | 125 | 96
Sublease income | 0 | (1) | 1
Total lease cost | 377 | 521 | 490
Assets Subject to Power Purchase Agreement |  |  |
Lease cost |  |  |
Operating lease cost | 112 | 162 | 165
Alabama Power |  |  |
Lease cost |  |  |
Operating lease cost | 16 | 59 | 58
Finance lease cost: |  |  |
Amortization of ROU assets | 2 | 1 | 1
Interest on lease obligations | 0 | 0 | 0
Total finance lease cost | 2 | 1 | 1
Short-term lease costs | 16 | 44 | 15
Variable lease cost | 0 | 13 | 4
Sublease income | 0 | 0 | 0
Total lease cost | 34 | 117 | 78
Alabama Power | Assets Subject to Power Purchase Agreement |  |  |
Lease cost |  |  |
Operating lease cost | 4 | 48 | 47
Georgia Power |  |  |
Lease cost |  |  |
Operating lease cost | 192 | 198 | 208
Finance lease cost: |  |  |
Amortization of ROU assets | 19 | 15 | 11
Interest on lease obligations | 17 | 17 | 16
Total finance lease cost | 36 | 32 | 27
Short-term lease costs | 16 | 13 | 24
Variable lease cost | 74 | 105 | 83
Sublease income | 0 | 0 | 0
Total lease cost | 318 | 348 | 342
Georgia Power | Assets Subject to Power Purchase Agreement |  |  |
Lease cost |  |  |
Operating lease cost | 174 | 180 | 184
Mississippi Power |  |  |
Lease cost |  |  |
Operating lease cost | 5 | 5 | 2
Finance lease cost: |  |  |
Amortization of ROU assets | 1 | 1 | 1
Interest on lease obligations | 0 | 1 | 1
Total finance lease cost | 1 | 2 | 2
Short-term lease costs | 0 | 0 | 0
Variable lease cost | 0 | 0 | 0
Sublease income | 0 | 0 | 0
Total lease cost | 6 | 7 | 4
Southern Power |  |  |
Lease cost |  |  |
Operating lease cost | 34 | 32 | 33
Finance lease cost: |  |  |
Amortization of ROU assets | 0 | 0 | 0
Interest on lease obligations | 0 | 0 | 0
Total finance lease cost | 0 | 0 | 0
Short-term lease costs | 0 | 0 | 0
Variable lease cost | 4 | 5 | 5
Sublease income | 0 | 0 | 0
Total lease cost | 38 | 37 | 38
Southern Company Gas |  |  |
Lease cost |  |  |
Operating lease cost | 12 | 15 | 19
Finance lease cost: |  |  |
Amortization of ROU assets | 0 | 0 | 0
Interest on lease obligations | 0 | 0 | 0
Total finance lease cost | 0 | 0 | 0
Short-term lease costs | 0 | 0 | 0
Variable lease cost | 0 | 0 | 0
Sublease income | 0 | 0 | 0
Total lease cost | $ 12 | $ 15 | $ 19

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