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CONTINGENCIES, COMMITMENTS, AND GUARANTEES - GAS Commitments (Details) - Southern Company Gas MMBTU in Millions, $ in Millions | 12 Months Ended
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Dec. 31, 2021 USD ($) MMBTU
Long-term Purchase Commitment [Line Items] |
Natural gas pipeline capacity | MMBTU | 56
Long-term purchase commitment amount | $ 222
Pipeline Charges, Storage Capacity, and Gas Supply |
Pipeline Charges, Storage Capacity, and Gas Supply |
2022 | 634
2023 | 455
2024 | 376
2025 | 275
2026 | 164
Thereafter | 910
Total | $ 2,814

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