v3.25.4
Schedule I—Condensed Financial Information of Registrant (Parent Company Only) - Narrative (Details) - USD ($)
 12 Months Ended
Aug. 11, 2023
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]        
Debt   $ 13,364,000,000 $ 10,588,000,000  
Series A Preferred Stock        
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]        
Preferred stock, dividend rate (as percent) 6.75%      
Parent Company        
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]        
Debt   3,547,000,000 2,311,000,000  
Dividends from subsidiaries   750,000,000 452,000,000 $ 1,082,000,000
Parent Company | Series A Preferred Stock        
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]        
Preferred stock, dividend rate (as percent) 6.75%      
Parent Company | Subsidiary | AAM        
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]        
Other receivables   0 121,000,000  
Outstanding net payable   685,000,000 0  
Parent Company | Subsidiary | Revolving Credit Facility | AHL Credit Facility | Line of Credit        
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]        
Line of credit facility, maximum borrowing capacity   500,000,000    
Debt   227,000,000 $ 142,000,000  
Parent Company | Subsidiary | Revolving Credit Facility | AHL | AHL Credit Facility        
SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Line Items]        
Line of credit facility, maximum borrowing capacity   $ 500,000,000