LEASES - Undiscounted Cash Flows to be Received Under PPAs Accounted for as Operating Leases (Details) $ in Millions	Dec. 31, 2022 USD ($)
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2023	$ 145
2024	114
2025	105
2026	104
2027	104
Thereafter	796
Total	1,368
Alabama Power
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2023	34
2024	6
2025	5
2026	3
2027	3
Thereafter	23
Total	74
Southern Power
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2023	88
2024	90
2025	74
2026	73
2027	74
Thereafter	166
Total	565
Southern Company Gas
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2023	36
2024	34
2025	29
2026	29
2027	28
Thereafter	382
Total	$ 538

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- Definition

Amount of lease payments to be received by lessor for operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI https://asc.fasb.org/extlink&oid=124258985&loc=SL77919396-209981

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- Definition

Amount of lease payment to be received by lessor for operating lease in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Amount of lease payment to be received by lessor for operating lease in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Amount of lease payment to be received by lessor for operating lease in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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Amount of lease payment to be received by lessor for operating lease after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Amount of lease payment to be received by lessor for operating lease in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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- Definition

Amount of lease payment to be received by lessor for operating lease in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

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