v3.25.2
Commitments and contingencies - Narrative (Details) - USD ($)
$ / shares in Units, $ in Millions
3 Months Ended 6 Months Ended
Dec. 30, 2024
Feb. 26, 2021
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Other Commitments [Line Items]            
Dividends paid to preference shareholders         $ 8.0 $ 8.0
Operating lease expense     $ 2.6 $ 2.5 $ 4.5 4.7
Merger warrants            
Other Commitments [Line Items]            
Warrants repurchased (in shares) 20,991,337          
Warrants price (in dollars per share) $ 3.56          
Liability-classified capital instruments | Series A preference shares            
Other Commitments [Line Items]            
Gains (losses) from the change in fair value       0.6   (3.3)
Liability-classified capital instruments | Merger warrants            
Other Commitments [Line Items]            
Gains (losses) from the change in fair value       $ 10.0   (2.0)
Sirius Group | Series A preference shares            
Other Commitments [Line Items]            
Dividends paid to preference shareholders           $ 0.0
Sirius Group | Series A preference shares            
Other Commitments [Line Items]            
Par value (in dollars per share)   $ 0.10        
Issuance of SiriusPoint common shares (in shares)   11,720,987