LEASES - Maturities of Lease Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Operating leases:
2024	$ 230
2025	203
2026	180
2027	159
2028	143
Thereafter	1,378
Total	2,293
Less: Present value discount	803
Operating lease obligations	1,490	$ 1,585
Finance leases:
2024	22
2025	27
2026	27
2027	27
2028	26
Thereafter	320
Total	449
Less: Present value discount	151
Finance lease obligations	298	314
Alabama Power
Operating leases:
2024	16
2025	14
2026	12
2027	10
2028	7
Thereafter	64
Total	123
Less: Present value discount	30
Operating lease obligations	93	76
Finance leases:
2024	2
2025	1
2026	1
2027	1
2028	1
Thereafter	0
Total	6
Less: Present value discount	1
Finance lease obligations	5	5
Georgia Power
Operating leases:
2024	172
2025	147
2026	142
2027	141
2028	135
Thereafter	303
Total	1,040
Less: Present value discount	165
Operating lease obligations	875	1,002
Finance leases:
2024	27
2025	36
2026	36
2027	36
2028	37
Thereafter	153
Total	325
Less: Present value discount	85
Finance lease obligations	240	238
Mississippi Power
Operating leases:
2024	4
2025	3
2026	2
2027	0
2028	0
Thereafter	1
Total	10
Less: Present value discount	1
Operating lease obligations	9	9
Finance leases:
2024	2
2025	2
2026	2
2027	2
2028	1
Thereafter	10
Total	19
Less: Present value discount	3
Finance lease obligations	16	17
Southern Power
Operating leases:
2024	36
2025	29
2026	29
2027	29
2028	30
Thereafter	1,000
Total	1,153
Less: Present value discount	607
Operating lease obligations	546	542
Finance leases:
2024	0
2025	0
2026	0
2027	0
2028	0
Thereafter	0
Total	0
Less: Present value discount	0
Finance lease obligations	0	0
Southern Company Gas
Operating leases:
2024	12
2025	12
2026	9
2027	4
2028	3
Thereafter	18
Total	58
Less: Present value discount	7
Operating lease obligations	51	60
Finance leases:
2024	0
2025	0
2026	0
2027	0
2028	0
Thereafter	0
Total	0
Less: Present value discount	0
Finance lease obligations	$ 0	$ 0