Common Stock, par value $0.01 per share Common Stock [Member] Entity Tax Identification Number Entity Tax Identification Number Series 2016B 1.850% Senior Notes Due 2026 [Member] Series 2016B 1.850% Senior Notes Due 2026 [Member] Series 2016B 1.850% Senior Notes Due 2026 [Member] Entity File Number Entity File Number Legal Entity [Axis] Legal Entity [Axis] Alabama Power Company Alabama Power [Member] Alabama Power. Cover [Abstract] Cover [Abstract] Title of 12(b) Security Title of 12(b) Security Local Phone Number Local Phone Number Class of Stock [Domain] Class of Stock [Domain] Soliciting Material Soliciting Material Entity Address, Address Line One Entity Address, Address Line One Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Southern Power Company Southern Power [Member] Southern Power. Entity Address, State or Province Entity Address, State or Province Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Georgia Power Company Georgia Power [Member] Georgia Power. Written Communications Written Communications Trading Symbol Trading Symbol City Area Code City Area Code Series 2025A 6.50% Junior Subordinated Notes due 2085 Series 2025A 6.50% Junior Subordinated Notes due 2085 [Member] Series 2025A 6.50% Junior Subordinated Notes due 2085 Series 2020A 4.95% Junior Subordinated Notes Due 2080 [Member] Series 2020A 4.95% Junior Subordinated Notes Due 2080 [Member] Series 2020A 4.95% Junior Subordinated Notes Due 2080 [Member] Series 2020C 4.20% Junior Subordinated Notes due 2060 Series 2020C 4.20% Junior Subordinated Notes due 2060 [Member] Series 2020C 4.20% Junior Subordinated Notes due 2060 Southern Company Gas Southern Company Gas [Member] Southern Company Gas [Member] Document Information [Table] Document Information [Table] Series 2021B 1.875% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2081 Series 2021B 1.875% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2081 [Member] Series 2021B 1.875% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2081 Document Period End Date Document Period End Date Amendment Flag Amendment Flag Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Entity Address, City or Town Entity Address, City or Town Series 2017B 5.25% Junior Subordinated Notes due 2077 Series 2017B 5.25% Junior Subordinated Notes Due 2077 [Member] Series 2017B 5.25% Junior Subordinated Notes Due 2077 [Member] Entity [Domain] Entity [Domain] Security Exchange Name Security Exchange Name 2025 Series A Corporate Units 2025 Series A Corporate Units [Member] 2025 Series A Corporate Units Mississippi Power Company Mississippi Power [Member] Mississippi Power. Document Information [Line Items] Document Information [Line Items] Document Type Document Type Series 2017A 5.00% Junior Subordinated Notes due 2077 Series 2017A 5.00% Junior Subordinated Notes due 2077 [Member] Series 2017A 5.00% Junior Subordinated Notes due 2077 Class of Stock [Axis] Class of Stock [Axis] Pre-commencement Tender Offer Pre-commencement Tender Offer Entity Central Index Key Entity Central Index Key Entity Emerging Growth Company Entity Emerging Growth Company