v3.25.2
Loss reserves - Narrative (Details) - USD ($)
$ in Millions
6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Scenario 2    
Liability for Claims and Claims Adjustment Expense [Line Items]    
Adjustments on prior accident year reserves   $ 131
Scenario 1    
Liability for Claims and Claims Adjustment Expense [Line Items]    
Losses and LAE incurred $ 145  
Scenario 2    
Liability for Claims and Claims Adjustment Expense [Line Items]    
Losses and LAE incurred   $ 135
Scenario Two    
Liability for Claims and Claims Adjustment Expense [Line Items]    
Adjustments on prior accident year reserves $ 95