v3.25.0.1
LEASES - Other Information (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 243 $ 253 $ 303
Operating cash flows from finance leases 15 15 11
Financing cash flows from finance leases 11 18 16
ROU assets obtained under operating leases 146 100 56
Reassessment of ROU assets under operating leases (7)   16
ROU assets obtained under finance leases $ 1 $ 3 118
Weighted-average remaining lease term in years:      
Operating leases 16 years 4 months 24 days 17 years 2 months 12 days  
Finance leases 16 years 16 years 8 months 12 days  
Weighted-average discount rate:      
Operating leases 4.73% 4.68%  
Finance leases 4.86% 4.85%  
Alabama Power      
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 19 $ 17 58
Operating cash flows from finance leases 0 0 0
Financing cash flows from finance leases 2 2 1
ROU assets obtained under operating leases 11 30 10
Reassessment of ROU assets under operating leases 0   0
ROU assets obtained under finance leases $ 0 $ 3 2
Weighted-average remaining lease term in years:      
Operating leases 10 years 2 months 12 days 11 years 1 month 6 days  
Finance leases 2 years 8 months 12 days 4 years 3 months 18 days  
Weighted-average discount rate:      
Operating leases 5.04% 5.02%  
Finance leases 4.05% 3.93%  
Georgia Power      
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 186 $ 199 206
Operating cash flows from finance leases 21 22 20
Financing cash flows from finance leases 23 16 10
ROU assets obtained under operating leases 609 26 17
Reassessment of ROU assets under operating leases 0   0
ROU assets obtained under finance leases $ 44 $ 18 116
Weighted-average remaining lease term in years:      
Operating leases 7 years 10 months 24 days 7 years 6 months  
Finance leases 10 years 1 month 6 days 10 years 7 months 6 days  
Weighted-average discount rate:      
Operating leases 4.73% 4.58%  
Finance leases 5.80% 5.95%  
Mississippi Power      
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 4 $ 5 5
Operating cash flows from finance leases 0 0 1
Financing cash flows from finance leases 1 1 1
ROU assets obtained under operating leases 0 1 9
Reassessment of ROU assets under operating leases 0   0
ROU assets obtained under finance leases $ 0 $ 0 0
Weighted-average remaining lease term in years:      
Operating leases 4 years 3 months 18 days 4 years 7 months 6 days  
Finance leases 10 years 10 months 24 days 11 years 10 months 24 days  
Weighted-average discount rate:      
Operating leases 3.83% 3.67%  
Finance leases 2.74% 2.74%  
Southern Power      
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 33 $ 33 30
Operating cash flows from finance leases 0 0 0
Financing cash flows from finance leases 0 0 0
ROU assets obtained under operating leases 10 7 0
Reassessment of ROU assets under operating leases (7)   16
ROU assets obtained under finance leases $ 0 $ 0 0
Weighted-average remaining lease term in years:      
Operating leases 32 years 3 months 18 days 33 years 1 month 6 days  
Weighted-average discount rate:      
Operating leases 4.88% 4.89%  
Southern Company Gas      
Cash paid for amounts included in the measurements of lease obligations:      
Operating cash flows from operating leases $ 12 $ 12 14
Operating cash flows from finance leases 0 0 0
Financing cash flows from finance leases 0 0 0
ROU assets obtained under operating leases 1 7 3
Reassessment of ROU assets under operating leases 0   0
ROU assets obtained under finance leases $ 0 $ 0 $ 0
Weighted-average remaining lease term in years:      
Operating leases 6 years 9 months 18 days 7 years  
Weighted-average discount rate:      
Operating leases 3.84% 3.80%