v3.20.2
REVENUE FROM CONTRACTS WITH CUSTOMERS AND LEASE INCOME - Disaggregate Revenue Sources (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Disaggregation of Revenue [Line Items]        
Operating revenues $ 4,765 $ 5,222 $ 10,053 $ 11,131
Revenues 4,620 5,098 9,638 10,510
Total retail electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 3,198 3,546 6,417 6,726
Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 1,430 1,491 2,801 2,818
Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 1,103 1,264 2,247 2,390
Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 642 766 1,323 1,474
Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 23 25 46 44
Natural gas distribution revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 585 557 1,584 1,717
Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 239 229 736 830
Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 58 65 188 235
Transportation        
Disaggregation of Revenue [Line Items]        
Operating revenues 234 213 499 469
Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 5 5 17 22
Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 49 45 144 161
Wholesale electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 325 370 639 723
PPA energy revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 167 208 326 398
PPA capacity revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 108 109 213 217
Non-PPA revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 50 53 100 108
Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 406 511 972 1,463
Wholesale gas services        
Disaggregation of Revenue [Line Items]        
Operating revenues 341 444 737 1,165
Gas marketing services        
Disaggregation of Revenue [Line Items]        
Operating revenues 57 55 220 276
Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 8 12 15 22
Other revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 251 238 441 502
Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other 728 1,050 1,599 2,413
Other adjustments        
Disaggregation of Revenue [Line Items]        
Other (873) (1,174) (2,014) (3,034)
ALABAMA POWER CO        
Disaggregation of Revenue [Line Items]        
Operating revenues 1,312 1,490 2,663 2,925
Revenues 1,365 1,513 2,716 2,921
ALABAMA POWER CO | Total retail electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 1,210 1,390 2,454 2,661
ALABAMA POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 549 592 1,103 1,151
ALABAMA POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 353 422 717 790
ALABAMA POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 302 369 623 707
ALABAMA POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 6 7 11 13
ALABAMA POWER CO | Natural gas distribution revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
ALABAMA POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
ALABAMA POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
ALABAMA POWER CO | Transportation        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
ALABAMA POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
ALABAMA POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
ALABAMA POWER CO | Wholesale electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 58 63 131 181
ALABAMA POWER CO | PPA energy revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 28 35 55 67
ALABAMA POWER CO | PPA capacity revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 25 25 52 52
ALABAMA POWER CO | Non-PPA revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 5 3 24 62
ALABAMA POWER CO | Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
ALABAMA POWER CO | Wholesale gas services        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
ALABAMA POWER CO | Gas marketing services        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
ALABAMA POWER CO | Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
ALABAMA POWER CO | Other revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 44 37 78 83
ALABAMA POWER CO | Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other 53 23 53 (4)
ALABAMA POWER CO | Other adjustments        
Disaggregation of Revenue [Line Items]        
Other 0 0 0 0
GEORGIA POWER CO        
Disaggregation of Revenue [Line Items]        
Operating revenues 1,935 2,069 3,830 3,894
Revenues 1,928 2,117 3,754 3,951
GEORGIA POWER CO | Total retail electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 1,794 1,943 3,572 3,650
GEORGIA POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 817 831 1,577 1,539
GEORGIA POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 689 770 1,409 1,463
GEORGIA POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 273 327 555 623
GEORGIA POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 15 15 31 25
GEORGIA POWER CO | Natural gas distribution revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
GEORGIA POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
GEORGIA POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
GEORGIA POWER CO | Transportation        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
GEORGIA POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
GEORGIA POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
GEORGIA POWER CO | Wholesale electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 22 31 44 58
GEORGIA POWER CO | PPA energy revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 7 17 15 28
GEORGIA POWER CO | PPA capacity revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 13 13 25 27
GEORGIA POWER CO | Non-PPA revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 2 1 4 3
GEORGIA POWER CO | Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
GEORGIA POWER CO | Wholesale gas services        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
GEORGIA POWER CO | Gas marketing services        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
GEORGIA POWER CO | Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
GEORGIA POWER CO | Other revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 119 95 214 186
GEORGIA POWER CO | Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other (7) 48 (76) 57
GEORGIA POWER CO | Other adjustments        
Disaggregation of Revenue [Line Items]        
Other 0 0 0 0
MISSISSIPPI POWER CO        
Disaggregation of Revenue [Line Items]        
Operating revenues 276 310 552 596
Revenues 283 313 559 600
MISSISSIPPI POWER CO | Total retail electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 194 213 391 415
MISSISSIPPI POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 64 68 121 128
MISSISSIPPI POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 61 72 121 137
MISSISSIPPI POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 67 70 145 144
MISSISSIPPI POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 2 3 4 6
MISSISSIPPI POWER CO | Natural gas distribution revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
MISSISSIPPI POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
MISSISSIPPI POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
MISSISSIPPI POWER CO | Transportation        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
MISSISSIPPI POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
MISSISSIPPI POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
MISSISSIPPI POWER CO | Wholesale electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 76 93 148 171
MISSISSIPPI POWER CO | PPA energy revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 2 3 4 5
MISSISSIPPI POWER CO | PPA capacity revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 1 1 2 2
MISSISSIPPI POWER CO | Non-PPA revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 73 89 142 164
MISSISSIPPI POWER CO | Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
MISSISSIPPI POWER CO | Wholesale gas services        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
MISSISSIPPI POWER CO | Gas marketing services        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
MISSISSIPPI POWER CO | Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
MISSISSIPPI POWER CO | Other revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 6 4 13 10
MISSISSIPPI POWER CO | Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other 7 3 7 4
MISSISSIPPI POWER CO | Other adjustments        
Disaggregation of Revenue [Line Items]        
Other 0 0 0 0
SOUTHERN POWER CO        
Disaggregation of Revenue [Line Items]        
Operating revenues 268 315 519 592
Revenues 439 510 814 953
SOUTHERN POWER CO | Total retail electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Natural gas distribution revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Transportation        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Wholesale electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 264 312 512 586
SOUTHERN POWER CO | PPA energy revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 134 163 259 314
SOUTHERN POWER CO | PPA capacity revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 71 81 136 163
SOUTHERN POWER CO | Non-PPA revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 59 68 117 109
SOUTHERN POWER CO | Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Wholesale gas services        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Gas marketing services        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN POWER CO | Other revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 4 3 7 6
SOUTHERN POWER CO | Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other 171 195 295 361
SOUTHERN POWER CO | Other adjustments        
Disaggregation of Revenue [Line Items]        
Other 0 0 0 0
SOUTHERN Co GAS        
Disaggregation of Revenue [Line Items]        
Operating revenues 991 1,068 2,556 3,180
Revenues 636 689 1,885 2,163
SOUTHERN Co GAS | Total retail electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN Co GAS | Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN Co GAS | Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN Co GAS | Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN Co GAS | Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN Co GAS | Natural gas distribution revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 585 557 1,584 1,717
SOUTHERN Co GAS | Residential        
Disaggregation of Revenue [Line Items]        
Operating revenues 239 229 736 830
SOUTHERN Co GAS | Commercial        
Disaggregation of Revenue [Line Items]        
Operating revenues 58 65 188 235
SOUTHERN Co GAS | Transportation        
Disaggregation of Revenue [Line Items]        
Operating revenues 234 213 499 469
SOUTHERN Co GAS | Industrial        
Disaggregation of Revenue [Line Items]        
Operating revenues 5 5 17 22
SOUTHERN Co GAS | Other        
Disaggregation of Revenue [Line Items]        
Operating revenues 49 45 144 161
SOUTHERN Co GAS | Wholesale electric revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN Co GAS | PPA energy revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN Co GAS | PPA capacity revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN Co GAS | Non-PPA revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN Co GAS | Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 406 511 972 1,463
SOUTHERN Co GAS | Wholesale gas services        
Disaggregation of Revenue [Line Items]        
Operating revenues 341 444 737 1,165
SOUTHERN Co GAS | Gas marketing services        
Disaggregation of Revenue [Line Items]        
Operating revenues 57 55 220 276
SOUTHERN Co GAS | Other natural gas revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 8 12 15 22
SOUTHERN Co GAS | Other revenues        
Disaggregation of Revenue [Line Items]        
Operating revenues 0 0 0 0
SOUTHERN Co GAS | Other revenue sources        
Disaggregation of Revenue [Line Items]        
Other 518 795 1,343 2,017
SOUTHERN Co GAS | Other adjustments        
Disaggregation of Revenue [Line Items]        
Other $ (873) $ (1,174) $ (2,014) $ (3,034)