Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Liabilities:
Collateral already posted, aggregate fair value	$ 189
Net Asset Value as a Practical Expedient (NAV)
Assets:
Net Asset Value as a Practical Expedient (NAV)	37
Net Asset Value as a Practical Expedient (NAV) | Nuclear Decommissioning Trusts
Assets:
Net Asset Value as a Practical Expedient (NAV)	37
ALABAMA POWER CO
Assets:
Energy-related derivatives	7	$ 4
Liabilities:
Energy-related derivatives	10	10
ALABAMA POWER CO | Net Asset Value as a Practical Expedient (NAV)
Assets:
Net Asset Value as a Practical Expedient (NAV)	37
ALABAMA POWER CO | Net Asset Value as a Practical Expedient (NAV) | Nuclear Decommissioning Trusts
Assets:
Net Asset Value as a Practical Expedient (NAV)	37
GEORGIA POWER CO
Assets:
Energy-related derivatives	7	6
Nuclear decommissioning trusts	37
Liabilities:
Energy-related derivatives	28	24
GEORGIA POWER CO | Net Asset Value as a Practical Expedient (NAV)
Assets:
Net Asset Value as a Practical Expedient (NAV)	0
GULF POWER CO
Assets:
Energy-related derivatives	0	0
Liabilities:
Energy-related derivatives	8	21
MISSISSIPPI POWER CO
Assets:
Energy-related derivatives	3	3
Liabilities:
Energy-related derivatives	9	9
SOUTHERN POWER CO
Assets:
Energy-related derivatives	125	132
Liabilities:
Energy-related derivatives	30	36
SOUTHERN Co GAS
Assets:
Energy-related derivatives	400	554
Liabilities:
Energy-related derivatives	516	660
Collateral already posted, aggregate fair value	189	$ 193
Fair Value, Measurements, Recurring
Assets:
Energy-related derivatives	421
Foreign currency derivatives	122
Nuclear decommissioning trusts	1,872
Cash equivalents	1,309
Total	3,778
Liabilities:
Energy-related derivatives	575
Interest rate derivatives	72
Foreign currency derivatives	23
Contingent consideration	22
Total	692
Fair Value, Measurements, Recurring | Weather Derivative
Assets:
Energy-related derivatives	5
Fair Value, Measurements, Recurring | Domestic equity
Assets:
Non-qualified deferred compensation trusts:	11
Fair Value, Measurements, Recurring | Foreign equity
Assets:
Non-qualified deferred compensation trusts:	6
Fair Value, Measurements, Recurring | Pooled funds – fixed income
Assets:
Non-qualified deferred compensation trusts:	13
Fair Value, Measurements, Recurring | Cash equivalents
Assets:
Non-qualified deferred compensation trusts:	15
Fair Value, Measurements, Recurring | Other
Assets:
Non-qualified deferred compensation trusts:	9
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Energy-related derivatives	271
Foreign currency derivatives	0
Nuclear decommissioning trusts	828
Cash equivalents	1,309
Total	2,432
Liabilities:
Energy-related derivatives	416
Interest rate derivatives	0
Foreign currency derivatives	0
Contingent consideration	0
Total	416
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Domestic equity
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Foreign equity
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pooled funds – fixed income
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash equivalents
Assets:
Non-qualified deferred compensation trusts:	15
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other
Assets:
Non-qualified deferred compensation trusts:	9
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Energy-related derivatives	150
Foreign currency derivatives	122
Nuclear decommissioning trusts	1,007
Cash equivalents	0
Total	1,309
Liabilities:
Energy-related derivatives	159
Interest rate derivatives	72
Foreign currency derivatives	23
Contingent consideration	0
Total	254
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Domestic equity
Assets:
Non-qualified deferred compensation trusts:	11
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Foreign equity
Assets:
Non-qualified deferred compensation trusts:	6
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Pooled funds – fixed income
Assets:
Non-qualified deferred compensation trusts:	13
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Cash equivalents
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) | Other
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Energy-related derivatives	0
Foreign currency derivatives	0
Nuclear decommissioning trusts	0
Cash equivalents	0
Total	0
Liabilities:
Energy-related derivatives	0
Interest rate derivatives	0
Foreign currency derivatives	0
Contingent consideration	22
Total	22
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Domestic equity
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Foreign equity
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Pooled funds – fixed income
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Cash equivalents
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3) | Other
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO
Assets:
Energy-related derivatives	7
Cash equivalents	513
Total	1,458
Liabilities:
Energy-related derivatives	10
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Domestic equity
Assets:
Nuclear decommissioning trusts	558
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Foreign equity
Assets:
Nuclear decommissioning trusts	116
Fair Value, Measurements, Recurring | ALABAMA POWER CO | U.S. Treasury and government agency securities
Assets:
Nuclear decommissioning trusts	18
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Corporate bonds
Assets:
Nuclear decommissioning trusts	180
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Mortgage and asset backed securities
Assets:
Nuclear decommissioning trusts	22
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Private equity
Assets:
Nuclear decommissioning trusts	37
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Other
Assets:
Nuclear decommissioning trusts	7
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Energy-related derivatives	0
Cash equivalents	513
Total	1,075
Liabilities:
Energy-related derivatives	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Domestic equity
Assets:
Nuclear decommissioning trusts	469
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Foreign equity
Assets:
Nuclear decommissioning trusts	60
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury and government agency securities
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds
Assets:
Nuclear decommissioning trusts	26
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage and asset backed securities
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Private equity
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other
Assets:
Nuclear decommissioning trusts	7
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Other Observable Inputs (Level 2)
Assets:
Energy-related derivatives	7
Cash equivalents	0
Total	346
Liabilities:
Energy-related derivatives	10
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Other Observable Inputs (Level 2) | Domestic equity
Assets:
Nuclear decommissioning trusts	89
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Other Observable Inputs (Level 2) | Foreign equity
Assets:
Nuclear decommissioning trusts	56
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Other Observable Inputs (Level 2) | U.S. Treasury and government agency securities
Assets:
Nuclear decommissioning trusts	18
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Other Observable Inputs (Level 2) | Corporate bonds
Assets:
Nuclear decommissioning trusts	154
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Other Observable Inputs (Level 2) | Mortgage and asset backed securities
Assets:
Nuclear decommissioning trusts	22
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Other Observable Inputs (Level 2) | Private equity
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Other Observable Inputs (Level 2) | Other
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Unobservable Inputs (Level 3)
Assets:
Energy-related derivatives	0
Cash equivalents	0
Total	0
Liabilities:
Energy-related derivatives	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Unobservable Inputs (Level 3) | Domestic equity
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Unobservable Inputs (Level 3) | Foreign equity
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Unobservable Inputs (Level 3) | U.S. Treasury and government agency securities
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Unobservable Inputs (Level 3) | Corporate bonds
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Unobservable Inputs (Level 3) | Mortgage and asset backed securities
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Unobservable Inputs (Level 3) | Private equity
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Unobservable Inputs (Level 3) | Other
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO
Assets:
Energy-related derivatives	8
Cash equivalents	350
Total	1,291
Liabilities:
Energy-related derivatives	22
Interest rate derivatives	6
Total	28
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Domestic equity
Assets:
Nuclear decommissioning trusts	251
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Foreign equity
Assets:
Nuclear decommissioning trusts	134
Fair Value, Measurements, Recurring | GEORGIA POWER CO | U.S. Treasury and government agency securities
Assets:
Nuclear decommissioning trusts	236
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Municipal bonds
Assets:
Nuclear decommissioning trusts	82
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Corporate bonds
Assets:
Nuclear decommissioning trusts	163
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Mortgage and asset backed securities
Assets:
Nuclear decommissioning trusts	42
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Other
Assets:
Non-qualified deferred compensation trusts:	25
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Energy-related derivatives	0
Cash equivalents	350
Total	616
Liabilities:
Energy-related derivatives	0
Interest rate derivatives	0
Total	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Domestic equity
Assets:
Nuclear decommissioning trusts	250
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Foreign equity
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury and government agency securities
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipal bonds
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate bonds
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage and asset backed securities
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other
Assets:
Non-qualified deferred compensation trusts:	16
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Other Observable Inputs (Level 2)
Assets:
Energy-related derivatives	8
Cash equivalents	0
Total	675
Liabilities:
Energy-related derivatives	22
Interest rate derivatives	6
Total	28
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Other Observable Inputs (Level 2) | Domestic equity
Assets:
Nuclear decommissioning trusts	1
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Other Observable Inputs (Level 2) | Foreign equity
Assets:
Nuclear decommissioning trusts	134
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Other Observable Inputs (Level 2) | U.S. Treasury and government agency securities
Assets:
Nuclear decommissioning trusts	236
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Other Observable Inputs (Level 2) | Municipal bonds
Assets:
Nuclear decommissioning trusts	82
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Other Observable Inputs (Level 2) | Corporate bonds
Assets:
Nuclear decommissioning trusts	163
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Other Observable Inputs (Level 2) | Mortgage and asset backed securities
Assets:
Nuclear decommissioning trusts	42
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Other Observable Inputs (Level 2) | Other
Assets:
Non-qualified deferred compensation trusts:	9
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Unobservable Inputs (Level 3)
Assets:
Energy-related derivatives	0
Cash equivalents	0
Total	0
Liabilities:
Energy-related derivatives	0
Interest rate derivatives	0
Total	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Unobservable Inputs (Level 3) | Domestic equity
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Unobservable Inputs (Level 3) | Foreign equity
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Unobservable Inputs (Level 3) | U.S. Treasury and government agency securities
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Unobservable Inputs (Level 3) | Municipal bonds
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Unobservable Inputs (Level 3) | Corporate bonds
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Unobservable Inputs (Level 3) | Mortgage and asset backed securities
Assets:
Nuclear decommissioning trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Unobservable Inputs (Level 3) | Other
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | GULF POWER CO
Assets:
Cash equivalents	27
Liabilities:
Energy-related derivatives	8
Fair Value, Measurements, Recurring | GULF POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	27
Liabilities:
Energy-related derivatives	0
Fair Value, Measurements, Recurring | GULF POWER CO | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	0
Liabilities:
Energy-related derivatives	8
Fair Value, Measurements, Recurring | GULF POWER CO | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0
Liabilities:
Energy-related derivatives	0
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO
Assets:
Energy-related derivatives	3
Cash equivalents	346
Total	349
Liabilities:
Energy-related derivatives	9
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Energy-related derivatives	0
Cash equivalents	346
Total	346
Liabilities:
Energy-related derivatives	0
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO | Significant Other Observable Inputs (Level 2)
Assets:
Energy-related derivatives	3
Cash equivalents	0
Total	3
Liabilities:
Energy-related derivatives	9
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO | Significant Unobservable Inputs (Level 3)
Assets:
Energy-related derivatives	0
Cash equivalents	0
Total	0
Liabilities:
Energy-related derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN POWER CO
Assets:
Energy-related derivatives	3
Foreign currency derivatives	122
Total	125
Liabilities:
Energy-related derivatives	7
Foreign currency derivatives	23
Contingent consideration	22
Total	52
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Energy-related derivatives	0
Foreign currency derivatives	0
Total	0
Liabilities:
Energy-related derivatives	0
Foreign currency derivatives	0
Contingent consideration	0
Total	0
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Significant Other Observable Inputs (Level 2)
Assets:
Energy-related derivatives	3
Foreign currency derivatives	122
Total	125
Liabilities:
Energy-related derivatives	7
Foreign currency derivatives	23
Contingent consideration	0
Total	30
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Significant Unobservable Inputs (Level 3)
Assets:
Energy-related derivatives	0
Foreign currency derivatives	0
Total	0
Liabilities:
Energy-related derivatives	0
Foreign currency derivatives	0
Contingent consideration	22
Total	22
Fair Value, Measurements, Recurring | SOUTHERN Co GAS
Assets:
Energy-related derivatives	400
Cash equivalents	26
Total	460
Liabilities:
Energy-related derivatives	517
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Domestic equity
Assets:
Non-qualified deferred compensation trusts:	11
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Foreign equity
Assets:
Non-qualified deferred compensation trusts:	6
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Pooled funds – fixed income
Assets:
Non-qualified deferred compensation trusts:	13
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Other
Assets:
Non-qualified deferred compensation trusts:	4
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Energy-related derivatives	271
Cash equivalents	26
Total	301
Liabilities:
Energy-related derivatives	416
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Quoted Prices in Active Markets for Identical Assets (Level 1) | Domestic equity
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Quoted Prices in Active Markets for Identical Assets (Level 1) | Foreign equity
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pooled funds – fixed income
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other
Assets:
Non-qualified deferred compensation trusts:	4
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Other Observable Inputs (Level 2)
Assets:
Energy-related derivatives	129
Cash equivalents	0
Total	159
Liabilities:
Energy-related derivatives	101
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Other Observable Inputs (Level 2) | Domestic equity
Assets:
Non-qualified deferred compensation trusts:	11
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Other Observable Inputs (Level 2) | Foreign equity
Assets:
Non-qualified deferred compensation trusts:	6
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Other Observable Inputs (Level 2) | Pooled funds – fixed income
Assets:
Non-qualified deferred compensation trusts:	13
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Other Observable Inputs (Level 2) | Other
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Unobservable Inputs (Level 3)
Assets:
Energy-related derivatives	0
Cash equivalents	0
Total	0
Liabilities:
Energy-related derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Unobservable Inputs (Level 3) | Domestic equity
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Unobservable Inputs (Level 3) | Foreign equity
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Unobservable Inputs (Level 3) | Pooled funds – fixed income
Assets:
Non-qualified deferred compensation trusts:	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Unobservable Inputs (Level 3) | Other
Assets:
Non-qualified deferred compensation trusts:	$ 0