XML 104 R88.htm IDEA: XBRL DOCUMENT v3.21.1
Reserves for Losses and Adjustment Expenses Short-duration insurance contracts - Reconciliation of Claims Development (Details) - USD ($)
$ in Millions
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Liability for claims and claim adjustment expenses, net of reinsurance $ 4,266.0 $ 4,815.5    
Reinsurance recoverable on unpaid losses 3,195.2 2,319.8    
Unallocated claims incurred 50.3 44.0    
Other 0.5 (0.1)    
Liability for unpaid claims and claim adjustment expense, aggregate reconciling items (295.9) (183.5)    
Losses and loss adjustment expenses 7,165.3 6,951.8 $ 7,074.2 $ 6,749.5
Property Insurance        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Liability for claims and claim adjustment expenses, net of reinsurance 226.8 190.7    
Casualty Insurance        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Liability for claims and claim adjustment expenses, net of reinsurance 618.7 669.2    
Marine, Aviation and Energy Insurance        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Liability for claims and claim adjustment expenses, net of reinsurance 431.4 591.5    
Financial and Professional Insurance        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Liability for claims and claim adjustment expenses, net of reinsurance 738.5 657.4    
Insurance lines        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Liability for claims and claim adjustment expenses, net of reinsurance 2,015.4 2,108.8    
Reinsurance recoverable on unpaid losses 2,140.3 1,772.8    
Property Catastrophe and Other Property Reinsurance        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Liability for claims and claim adjustment expenses, net of reinsurance 631.0 528.6    
Casualty Reinsurance        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Liability for claims and claim adjustment expenses, net of reinsurance 1,084.2 1,602.2    
Specialty Reinsurance        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Liability for claims and claim adjustment expenses, net of reinsurance 535.4 575.9    
Reinsurance lines        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Liability for claims and claim adjustment expenses, net of reinsurance 2,250.6 2,706.7    
Reinsurance recoverable on unpaid losses 1,054.9 547.0    
Insurance lines other than short-duration        
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]        
Other reinsurance balances recoverable $ (346.7) $ (227.4)