v3.26.1
Segment and Related Information - Schedule of Southern Power (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting [Line Items]        
Operating revenues $ 6,977 $ 6,973 $ 15,374 $ 14,748
Other segment items 3,472 3,617 8,138 7,812
Depreciation and amortization(b) 1,434 1,323 2,854 2,608
Earnings from equity method investments 86 10 136 43
Interest expense 796 874 1,573 1,588
Income taxes (benefit) 187 289 414 569
Net income 1,174 880 2,531 2,214
Loss from extinguishment of debt   129 11 129
Loss from extinguishment of debt, net of tax   97 8 97
Operating Segments        
Segment Reporting [Line Items]        
Operating revenues 6,792 6,783 15,005 14,378
Other segment items 3,306 3,447 7,824 7,492
Depreciation and amortization(b) 1,417 1,306 2,820 2,575
Earnings from equity method investments 44 27 89 64
Interest expense 484 452 954 885
Income taxes (benefit) 259 401 563 755
Net income 1,370 1,204 2,933 2,735
Eliminations        
Segment Reporting [Line Items]        
Operating revenues (38) (35) (72) (84)
Other segment items (27) (23) (68) (81)
Depreciation and amortization(b) 0 0 0 0
Earnings from equity method investments 0 0 0 0
Interest expense 0 0 0 0
Income taxes (benefit) 0 0 0 0
Net income (11) (12) (4) (3)
All Other        
Segment Reporting [Line Items]        
Operating revenues 223 225 441 454
Other segment items 193 193 382 401
Depreciation and amortization(b) 17 17 34 33
Earnings from equity method investments 42 (17) 47 (21)
Interest expense 312 422 619 703
Income taxes (benefit) (72) (112) (149) (186)
Net income (185) (312) (398) (518)
SOUTHERN POWER CO        
Segment Reporting [Line Items]        
Operating revenues 535 546 1,216 1,113
Depreciation and amortization(b) 280 177 558 329
Earnings from equity method investments     0 0
Interest expense 28 24 55 50
Income taxes (benefit) (77) (2) (147) (3)
Net income (25) 51 (22) 138
SOUTHERN POWER CO | Kay Wind Facility        
Segment Reporting [Line Items]        
Depreciation before tax 140 42 293 69
Depreciation after tax 109 31 228 51
Reportable Segment | SOUTHERN POWER CO        
Segment Reporting [Line Items]        
Operating revenues 535 546 1,216 1,113
Other segment items 329 296 772 599
Depreciation and amortization(b) 280 177 558 329
Interest expense 28 24 55 50
Income taxes (benefit) (77) (2) (147) (3)
Net income (25) 51 (22) 138
Traditional Electric Operating Companies | Operating Segments        
Segment Reporting [Line Items]        
Operating revenues 5,396 5,380 10,878 10,692
Other segment items 2,501 2,674 5,360 5,468
Depreciation and amortization(b) 967 957 1,908 1,905
Earnings from equity method investments 12 4 11 2
Interest expense 367 336 705 652
Income taxes (benefit) 304 370 534 596
Net income 1,269 1,047 2,382 2,073
SOUTHERN POWER CO | Operating Segments        
Segment Reporting [Line Items]        
Operating revenues 535 546 1,216 1,113
Other segment items 329 296 772 599
Depreciation and amortization(b) 280 177 558 329
Earnings from equity method investments 0 0 0 0
Interest expense 28 24 55 50
Income taxes (benefit) (77) (2) (147) (3)
Net income (25) 51 (22) 138
Electric Utilities | Operating Segments        
Segment Reporting [Line Items]        
Operating revenues 5,826 5,804 11,848 11,560
Other segment items 2,752 2,848 5,913 5,822
Depreciation and amortization(b) 1,232 1,134 2,451 2,234
Earnings from equity method investments 12 4 11 2
Interest expense 383 360 748 702
Income taxes (benefit) 227 368 387 593
Net income 1,244 1,098 2,360 2,211
Electric Utilities | Eliminations        
Segment Reporting [Line Items]        
Operating revenues (105) (122) (246) (245)
Other segment items (78) (122) (219) (245)
Depreciation and amortization(b) (15) 0 (15) 0
Earnings from equity method investments 0 0 0 0
Interest expense (12) 0 (12) 0
Income taxes (benefit) 0 0 0 0
Net income 0 0 0 0
SOUTHERN Co GAS | Operating Segments        
Segment Reporting [Line Items]        
Operating revenues 966 979 3,157 2,818
Other segment items 554 599 1,911 1,670
Depreciation and amortization(b) 185 172 369 341
Earnings from equity method investments 32 23 78 62
Interest expense 101 92 206 183
Income taxes (benefit) 32 33 176 162
Net income $ 126 $ 106 $ 573 $ 524