PROPERTY, PLANT, AND EQUIPMENT - Property, Plant and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Electric utilities:
Generation	$ 51,756	$ 53,803
Transmission	14,201	13,406
Distribution	24,200	22,236
General/other	5,806	5,423
Electric utilities' plant in service	95,963	94,868
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	16,810	15,714
Storage facilities	1,553	1,315
Other	1,360	1,851
Southern Company Gas plant in service	19,723	18,880
Other plant in service	1,843	1,844
Total plant in service	117,529	115,592
Alabama Power
Electric utilities:
Generation	15,920	16,631
Transmission	5,658	5,334
Distribution	9,154	8,643
General/other	2,740	2,527
Electric utilities' plant in service	33,472	33,135
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	33,472	33,135
Georgia Power
Electric utilities:
Generation	17,755	19,184
Transmission	7,576	7,132
Distribution	13,819	12,437
General/other	2,729	2,579
Electric utilities' plant in service	41,879	41,332
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	41,879	41,332
Mississippi Power
Electric utilities:
Generation	2,826	2,791
Transmission	927	900
Distribution	1,228	1,156
General/other	273	259
Electric utilities' plant in service	5,254	5,106
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	5,254	5,106
Southern Power
Electric utilities:
Generation	14,619	14,551
Transmission	0	0
Distribution	0	0
General/other	39	34
Electric utilities' plant in service	14,658	14,585
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	14,658	14,585
Southern Company Gas
Electric utilities:
Generation	0	0
Transmission	0	0
Distribution	0	0
General/other	0	0
Electric utilities' plant in service	0	0
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	16,810	15,714
Storage facilities	1,553	1,315
Other	1,360	1,851
Southern Company Gas plant in service	19,723	18,880
Other plant in service	0	0
Total plant in service	$ 19,723	$ 18,880