Financing and Leases - Schedule of Credit Arrangements (Details) $ in Millions	Jun. 30, 2024 USD ($)
Line of Credit Facility [Line Items]
Expires, 2025	$ 580
Expires, 2026	650
Expires, 2027	275
Expires, 2028	6,400
Total	7,905
Unused	7,877
Expires within One Year	580
Southern Company parent
Line of Credit Facility [Line Items]
Expires, 2025	150
Expires, 2026	0
Expires, 2027	0
Expires, 2028	1,850
Total	2,000
Unused	1,998
Expires within One Year	150
ALABAMA POWER CO
Line of Credit Facility [Line Items]
Expires, 2025	0
Expires, 2026	650
Expires, 2027	0
Expires, 2028	700
Total	1,350
Unused	1,350
Expires within One Year	0
GEORGIA POWER CO
Line of Credit Facility [Line Items]
Expires, 2025	300
Expires, 2026	0
Expires, 2027	0
Expires, 2028	1,750
Total	2,050
Unused	2,026
Expires within One Year	300
MISSISSIPPI POWER CO
Line of Credit Facility [Line Items]
Expires, 2025	0
Expires, 2026	0
Expires, 2027	275
Expires, 2028	0
Total	275
Unused	275
Expires within One Year	0
SOUTHERN POWER CO
Line of Credit Facility [Line Items]
Expires, 2025	0
Expires, 2026	0
Expires, 2027	0
Expires, 2028	600
Total	600
Unused	600
Expires within One Year	0
SOUTHERN POWER CO | Continuing Letter of Credit Facility A
Line of Credit Facility [Line Items]
Expires, 2025	75
Expires, 2026	100
Unused	10
SOUTHERN POWER CO | Continuing Letter of Credit Facility B
Line of Credit Facility [Line Items]
Unused	11
SOUTHERN Co GAS
Line of Credit Facility [Line Items]
Expires, 2025	100
Expires, 2026	0
Expires, 2027	0
Expires, 2028	1,500
Total	1,600
Unused	1,598
Expires within One Year	100
SEGCO
Line of Credit Facility [Line Items]
Expires, 2025	30
Expires, 2026	0
Expires, 2027	0
Expires, 2028	0
Total	30
Unused	30
Expires within One Year	30
Southern Company and Southern Power
Line of Credit Facility [Line Items]
Expires, 2028	2,450
Southern Company Gas Capital
Line of Credit Facility [Line Items]
Expires, 2028	800
Nicor Gas
Line of Credit Facility [Line Items]
Expires, 2024	100
Expires, 2028	$ 700