FINANCING - Maturities of Long-Term Debt (Details) $ in Millions	Dec. 31, 2019 USD ($)
Debt Disclosure [Line Items]
2020	$ 2,991
2021	3,214
2022	2,003
2023	2,413
2024	492
Alabama Power
Debt Disclosure [Line Items]
2020	251
2021	311
2022	751
2023	301
2024	22
Georgia Power
Debt Disclosure [Line Items]
2020	1,025
2021	397
2022	527
2023	175
2024	477
Mississippi Power
Debt Disclosure [Line Items]
2020	281
2021	270
2022	0
2023	0
2024	0
Southern Power
Debt Disclosure [Line Items]
2020	825
2021	300
2022	677
2023	290
2024	0
Southern Company Gas
Debt Disclosure [Line Items]
2020	0
2021	330
2022	46
2023	400
2024	$ 0

[Line Items] for Debt Disclosure [Table]

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- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24072-122690

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6802200&loc=d3e1835-112601

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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+ References

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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