v3.25.1
Fair Value Measurements - Funds Held By Reinsured Companies - Embedded Derivative (Details)
$ in Millions
3 Months Ended
Mar. 31, 2025
USD ($)
Mar. 31, 2024
USD ($)
Significant Unobservable Inputs (Level 3) | Monte Carlo simulation model; Discounted cash flow analysis    
Funds Held Under Reinsurance Agreements, Asset [Roll Forward]    
Embedded derivative $ 4  
Average | Significant Unobservable Inputs (Level 3) | Volatility rate | Monte Carlo simulation model; Discounted cash flow analysis    
Funds Held Under Reinsurance Agreements, Asset [Roll Forward]    
Embedded derivative, measurement input 0.0346  
Average | Significant Unobservable Inputs (Level 3) | Expected loss payments | Monte Carlo simulation model; Discounted cash flow analysis    
Funds Held Under Reinsurance Agreements, Asset [Roll Forward]    
Embedded derivative, measurement input 210  
Embedded derivatives    
Funds Held Under Reinsurance Agreements, Asset [Roll Forward]    
Beginning fair value $ 5 $ 40
Total fair value changes (1) (18)
Ending fair value $ 4 $ 22