XML 56 R1.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Cover Page - USD ($)
$ in Billions
 12 Months Ended
Dec. 31, 2019
Jan. 31, 2020
Jun. 28, 2019
Document Information [Line Items]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2019    
Document Transition Report false    
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    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Shell Company false    
Entity Public Float     $ 57.8
Entity Common Stock, Shares Outstanding (in shares)   1,054,228,409  
Documents Incorporated by Reference
Documents incorporated by reference: specified portions of The Southern Company's Definitive Proxy Statement on Schedule 14A relating to the 2020 Annual Meeting of Stockholders are incorporated by reference into PART III. In addition, specified portions of Alabama Power Company's Definitive Proxy Statement on Schedule 14A relating to its 2020 Annual Meeting of Shareholders are incorporated by reference into PART III.
    
Entity Central Index Key 0000092122    
Amendment Flag false    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Current Fiscal Year End Date --12-31    
Entity Emerging Growth Company false    
Entity Small Business 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    
2019 Series A Corporate Units      
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      
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    
Alabama Power      
Document Information [Line Items]      
Entity File Number 1-3164    
Entity Registrant Name Alabama Power Company    
Entity Tax Identification Number 63-0004250    
Entity Incorporation, State or Country Code AL    
Entity Address, Address Line One 600 North 18th Street    
Entity Address, City or Town Birmingham    
Entity Address, State or Province AL    
Entity Address, Postal Zip Code 35203    
City Area Code 205    
Local Phone Number 257-1000    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding (in shares)   30,537,500  
Entity Central Index Key 0000003153    
Entity Emerging Growth Company false    
Entity Small Business false    
Alabama Power | 5.00% Series Class A Preferred Stock      
Document Information [Line Items]      
Title of 12(b) Security 5.00% Series Class A Preferred Stock    
Trading Symbol ALP PR Q    
Security Exchange Name NYSE    
Alabama Power | Preferred Stock, Cumulative, $100 Par Value, 4.20% Series      
Document Information [Line Items]      
Title of 12(g) Security 4.20% Series    
Alabama Power | Preferred Stock, Cumulative, $100 Par Value, 4.52% Series      
Document Information [Line Items]      
Title of 12(g) Security 4.52% Series    
Alabama Power | Preferred Stock, Cumulative, $100 Par Value, 4.60% Series      
Document Information [Line Items]      
Title of 12(g) Security 4.60% Series    
Alabama Power | Preferred Stock, Cumulative, $100 Par Value, 4.64% Series      
Document Information [Line Items]      
Title of 12(g) Security 4.64% Series    
Alabama Power | Preferred Stock, Cumulative, $100 Par Value, 4.72% Series      
Document Information [Line Items]      
Title of 12(g) Security 4.72% Series    
Alabama Power | Preferred Stock, Cumulative, $100 Par Value, 4.92% Series      
Document Information [Line Items]      
Title of 12(g) Security 4.92% Series    
Georgia Power      
Document Information [Line Items]      
Entity File Number 1-6468    
Entity Registrant Name Georgia Power Company    
Entity Tax Identification Number 58-0257110    
Entity Incorporation, State or Country Code GA    
Entity Address, Address Line One 241 Ralph McGill Boulevard, N.E.    
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 506-6526    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding (in shares)   9,261,500  
Entity Central Index Key 0000041091    
Entity Emerging Growth Company false    
Entity Small Business false    
Georgia Power | Series 2017A 5.00% Junior Subordinated Notes due 2077      
Document Information [Line Items]      
Title of 12(b) Security Series 2017A 5.00% Junior Subordinated Notes due 2077    
Trading Symbol GPJA    
Security Exchange Name NYSE    
Mississippi Power      
Document Information [Line Items]      
Entity File Number 001-11229    
Entity Registrant Name Mississippi Power Company    
Entity Tax Identification Number 64-0205820    
Entity Incorporation, State or Country Code MS    
Entity Address, Address Line One 2992 West Beach Boulevard    
Entity Address, City or Town Gulfport    
Entity Address, State or Province MS    
Entity Address, Postal Zip Code 39501    
City Area Code 228    
Local Phone Number 864-1211    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding (in shares)   1,121,000  
Entity Central Index Key 0000066904    
Entity Emerging Growth Company false    
Entity Small Business false    
Southern Power      
Document Information [Line Items]      
Entity File Number 001-37803    
Entity Registrant Name Southern Power Company    
Entity Tax Identification Number 58-2598670    
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    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding (in shares)   1,000  
Entity Central Index Key 0001160661    
Entity Emerging Growth Company false    
Entity Small Business false    
Southern Power | Series 2016A 1.000% Senior Notes due 2022      
Document Information [Line Items]      
Title of 12(b) Security Series 2016A 1.000% Senior Notes due 2022    
Trading Symbol SO/22B    
Security Exchange Name NYSE    
Southern Power | Series 2016B 1.850% Senior Notes due 2026      
Document Information [Line Items]      
Title of 12(b) Security Series 2016B 1.850% Senior Notes due 2026    
Trading Symbol SO/26A    
Security Exchange Name NYSE    
Southern Company Gas      
Document Information [Line Items]      
Entity File Number 1-14174    
Entity Registrant Name Southern Company Gas    
Entity Tax Identification Number 58-2210952    
Entity Incorporation, State or Country Code GA    
Entity Address, Address Line One Ten Peachtree Place, N.E.    
Entity Address, City or Town Atlanta    
Entity Address, State or Province GA    
Entity Address, Postal Zip Code 30309    
City Area Code 404    
Local Phone Number 584-4000    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Shell Company false    
Entity Common Stock, Shares Outstanding (in shares)   100  
Entity Central Index Key 0001004155    
Entity Emerging Growth Company false    
Entity Small Business false