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Segment and Related Information - Schedule of Financial Data for Business Segments (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023 | Dec. 31, 2023
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | $ 6,463 | $ 5,748 | $ 13,109 | $ 12,228 |
Net income | 1,203 | 838 | 2,332 | 1,700 |
Goodwill | 5,161 |  | 5,161 |  | $ 5,161
Total assets | 141,937 |  | 141,937 |  | 139,331
Credit on plant vogtle units 3 and 4 | 21 | 0 | 21 | 0 |
SOUTHERN POWER CO |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 524 | 525 | 997 | 1,033 |
Net income | 86 | 85 | 182 | 187 |
Total assets | 12,764 |  | 12,764 |  | 12,761
SOUTHERN POWER CO | Disposal Group, Disposed of by Sale | Spare Parts |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Gain (loss) on sale |  |  | 16 |  |
Gain (loss) on sale, after tax |  |  | 12 |  |
SOUTHERN Co GAS |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 831 | 852 | 2,538 | 2,728 |
Net income | 108 | 85 | 517 | 393 |
Goodwill | 5,015 |  | 5,015 |  | 5,015
Total assets | 25,055 |  | 25,055 |  | 25,083
Nicor Gas |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Pre-tax charge to income |  |  | 38 |  |
After-tax charge to income |  |  | 28 |  |
GEORGIA POWER CO |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 2,875 | 2,391 | 5,273 | 4,567 |
Total assets | 58,795 |  | 58,795 |  | 56,817
Credit on plant vogtle units 3 and 4 | 21 | 0 | 21 | 0 |
After tax credit on plant vogtle units 3 and 4 | 16 |  |  |  |
Electric Utilities |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 5,456 | 4,764 | 10,271 | 9,247 |
SOUTHERN Co GAS |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 831 | 852 | 2,538 | 2,728 |
Gas distribution operations | SOUTHERN Co GAS |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Goodwill | 4,034 |  | 4,034 |  | 4,034
Operating Segments | SOUTHERN Co GAS |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 827 | 847 | 2,533 | 2,719 |
Net income | 111 | 86 | 508 | 387 |
Total assets | 26,199 |  | 26,199 |  | 26,055
Operating Segments | Electric Utilities |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 5,456 | 4,764 | 10,271 | 9,247 |
Net income | 1,278 | 908 | 2,194 | 1,620 |
Goodwill | 2 |  | 2 |  | 2
Total assets | 114,706 |  | 114,706 |  | 112,645
Operating Segments | Traditional Electric Operating Companies |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 5,025 | 4,359 | 9,463 | 8,472 |
Net income | 1,192 | 823 | 2,012 | 1,433 |
Goodwill | 0 |  | 0 |  | 0
Total assets | 102,528 |  | 102,528 |  | 100,429
Operating Segments | SOUTHERN POWER CO |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 524 | 525 | 997 | 1,033 |
Net income | 86 | 85 | 182 | 187 |
Goodwill | 2 |  | 2 |  | 2
Total assets | 12,764 |  | 12,764 |  | 12,761
Operating Segments | SOUTHERN Co GAS |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 831 | 852 | 2,538 | 2,728 |
Net income | 108 | 85 | 517 | 393 |
Goodwill | 5,015 |  | 5,015 |  | 5,015
Total assets | 25,055 |  | 25,055 |  | 25,083
Operating Segments | All Other |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 222 | 180 | 383 | 346 |
Net income | (181) | (157) | (368) | (311) |
Goodwill | 144 |  | 144 |  | 144
Total assets | 2,828 |  | 2,828 |  | 2,446
Operating Segments | All Other | SOUTHERN Co GAS |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 7 | 9 | 13 | 22 |
Net income | (3) | (1) | 9 | 6 |
Total assets | 9,795 |  | 9,795 |  | 9,675
Operating Segments | Gas distribution operations | SOUTHERN Co GAS |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | 749 | 764 | 2,212 | 2,383 |
Net income | 80 | 60 | 382 | 281 |
Total assets | 23,025 |  | 23,025 |  | 22,906
Eliminations |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | (46) | (48) | (83) | (93) |
Net income | (2) | 2 | (11) | (2) |
Goodwill | 0 |  | 0 |  | 0
Total assets | (652) |  | (652) |  | (843)
Eliminations | SOUTHERN Co GAS |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | (3) | (4) | (8) | (13) |
Net income | 0 | 0 | 0 | 0 |
Total assets | (10,939) |  | (10,939) |  | (10,647)
Eliminations | Electric Utilities |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Operating revenues | (93) | (120) | (189) | (258) |
Net income | 0 | $ 0 | 0 | $ 0 |
Goodwill | 0 |  | 0 |  | 0
Total assets | $ (586) |  | $ (586) |  | $ (545)

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