v3.23.3
Consolidated Entities and Equity Method Investments - Narrative (Details)
$ in Millions
 3 Months Ended 9 Months Ended
Mar. 31, 2023
USD ($)
Sep. 30, 2023
USD ($)
investor
Dec. 31, 2022
USD ($)
Schedule of Equity Method Investments [Line Items]      
Equity investments in unconsolidated subsidiaries   $ 1,376 $ 1,443
Assets   138,321 134,891
Liabilities   103,017 100,359
Southern Holdings Company      
Schedule of Equity Method Investments [Line Items]      
Equity investments in unconsolidated subsidiaries   126 112
SOUTHERN POWER CO      
Schedule of Equity Method Investments [Line Items]      
Equity investments in unconsolidated subsidiaries   0 49
Assets   13,090 13,081
Liabilities   $ 6,247 6,165
Proceeds from sale of equity method investments $ 50    
SP Solar Holdings I, LP | SOUTHERN POWER CO      
Schedule of Equity Method Investments [Line Items]      
Distribution made to limited partner, cash distributions paid, percentage   67.00%  
SP Solar Holdings I, LP | Global Atlantic      
Schedule of Equity Method Investments [Line Items]      
Distribution made to limited partner, cash distributions paid, percentage   33.00%  
Variable Interest Entity, Primary Beneficiary | SP Solar Holdings I, LP | SOUTHERN POWER CO      
Schedule of Equity Method Investments [Line Items]      
Assets   $ 5,800 5,900
Liabilities   400 400
Noncontrolling interests related to other partners' interests   1,100  
Variable Interest Entity, Primary Beneficiary | SP Wind | SOUTHERN POWER CO      
Schedule of Equity Method Investments [Line Items]      
Assets   2,200 2,200
Liabilities   184 169
Noncontrolling interests related to other partners' interests   $ 38 39
Distribution made to limited partner, cash distributions paid, percentage   60.00%  
Number of financial investors | investor   3  
Variable Interest Entity, Primary Beneficiary | SP Wind | Financial Investors      
Schedule of Equity Method Investments [Line Items]      
Distribution made to limited partner, cash distributions paid, percentage   40.00%  
Variable Interest Entity, Primary Beneficiary | Other Variable Interest Entities | SOUTHERN POWER CO      
Schedule of Equity Method Investments [Line Items]      
Assets   $ 1,700 1,800
Liabilities   200 200
Noncontrolling interests related to other partners' interests   $ 800 $ 800