Cover Page Document
Sep. 21, 2020
Document Information [Line Items]  
Document Type 8-K
Document Period End Date Sep. 15, 2020
Entity File Number 1-3526
Entity Registrant Name The Southern Company
Entity Tax Identification Number 58-0690070
Entity Incorporation, State or Country Code DE
Entity Address, Address Line One 30 Ivan Allen Jr. Boulevard, N.W
Entity Address, City or Town Atlanta
Entity Address, State or Province GA
Entity Address, Postal Zip Code 30308
City Area Code 404
Local Phone Number 506-5000
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Emerging Growth Company false
Entity Central Index Key 0000092122
Amendment Flag false
Common Stock, par value $5 per share  
Document Information [Line Items]  
Title of 12(b) Security Common Stock, par value $5 per share
Trading Symbol SO
Security Exchange Name NYSE
Series 2015A 6.25% Junior Subordinated Notes due 2075  
Document Information [Line Items]  
Title of 12(b) Security Series 2015A 6.25% Junior Subordinated Notes due 2075
Trading Symbol SOJA
Security Exchange Name NYSE
Series 2016A 5.25% Junior Subordinated Notes due 2076  
Document Information [Line Items]  
Title of 12(b) Security Series 2016A 5.25% Junior Subordinated Notes due 2076
Trading Symbol SOJB
Security Exchange Name NYSE
Series 2017B 5.25% Junior Subordinated Notes due 2077  
Document Information [Line Items]  
Title of 12(b) Security Series 2017B 5.25% Junior Subordinated Notes due 2077
Trading Symbol SOJC
Security Exchange Name NYSE
Series 2019A Corporate Units [Member]  
Document Information [Line Items]  
Title of 12(b) Security 2019 Series A Corporate Units
Trading Symbol SOLN
Security Exchange Name NYSE
Series 2020A 4.95% Junior Subordinated Notes Due 2080 [Member]  
Document Information [Line Items]  
Title of 12(b) Security Series 2020A 4.95% Junior Subordinated Notes due 2080
Trading Symbol SOJD
Security Exchange Name NYSE
Series 2020C 4.20% Junior Subordinated Notes [Member]  
Document Information [Line Items]  
Title of 12(b) Security Series 2020C 4.20% Junior Subordinated Notes
Trading Symbol SOJE
Security Exchange Name NYSE