v3.26.1
Asbestos - Schedule of Net Unfunded AFFA Liability, Net of Tax (Details) - USD ($)
$ in Millions
 3 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Net Unfunded AFFA Liability, net of tax    
Asbestos Net Liability [Roll Forward]    
Net Unfunded AFFA liability, net of tax, Beginning Balance $ (392.7)  
AICF operating costs paid - non claims-handling (0.6)  
Movement in income tax payable (41.6)  
Other movements 2.4  
Effect of foreign exchange (0.2)  
Net Unfunded AFFA liability, net of tax, Ending Balance (432.7)  
Deferred Tax Assets    
Asbestos Net Liability [Roll Forward]    
Asbestos, deferred tax assets, beginning balance 276.3 $ 282.5
Movement in income tax payable (6.8)  
Other movements (0.7)  
Effect of foreign exchange 1.3  
Asbestos, deferred tax assets, beginning balance 276.3  
Income Tax Payable    
Asbestos Net Liability [Roll Forward]    
Asbestos, income tax payable, beginning balance 40.2  
Movement in income tax payable (34.8)  
Other movements (0.1)  
Effect of foreign exchange 1.2  
Asbestos, income tax payable, ending balance 6.5  
Net Unfunded AFFA Liability    
Asbestos Net Liability [Roll Forward]    
Asbestos, net liability, beginning balance (715.4)  
AICF operating costs paid - non claims-handling (0.6)  
Other movements 3.2  
Effect of foreign exchange (2.7)  
Asbestos net liability, ending balance (715.5)  
Asbestos Liability    
Asbestos Net Liability [Roll Forward]    
Asbestos, net liability, beginning balance (1,008.6)  
Asbestos claims paid 32.8  
AICF claims-handling costs incurred (paid) 0.3  
Effect of foreign exchange (4.7)  
Asbestos net liability, ending balance (980.2)  
Insurance Receivables    
Asbestos Net Liability [Roll Forward]    
Asbestos, net liability, beginning balance 24.3  
Insurance recoveries (0.8)  
Effect of foreign exchange 0.2  
Asbestos net liability, ending balance 23.7  
Restricted Cash and Investments    
Asbestos Net Liability [Roll Forward]    
Asbestos, net liability, beginning balance 268.7  
Asbestos claims paid (32.8)  
AICF claims-handling costs incurred (paid) (0.3)  
AICF operating costs paid - non claims-handling (0.6)  
Insurance recoveries 0.8  
Other movements 2.4  
Effect of foreign exchange 1.8  
Asbestos net liability, ending balance 240.0  
Other Assets and Liabilities    
Asbestos Net Liability [Roll Forward]    
Asbestos, net liability, beginning balance 0.2  
Other movements 0.8  
Asbestos net liability, ending balance $ 1.0