v3.25.4
Total Equity - Non-Controlling Interests (Details)
$ / shares in Units, $ in Millions, $ in Millions
 12 Months Ended
Feb. 27, 2026
CAD ($)
$ / shares
Dec. 31, 2025
USD ($)
Dec. 31, 2024
USD ($)
Dec. 31, 2025
CAD ($)
$ / shares
Dec. 31, 2023
USD ($)
Total equity          
Carrying value   $ 4,359.8 $ 4,281.2    
Net earnings (loss) attributable to non-controlling interests   511.4 388.0    
Borrowings   $ 13,642.9 $ 11,753.7   $ 9,723.5
KI          
Total equity          
Economic ownership percentage   80.00% 80.00%    
Voting percentage   49.00% 49.00%    
Fairfax India          
Total equity          
Economic ownership percentage   57.10% 57.30%    
Voting percentage   4.80% 4.80%    
Recipe          
Total equity          
Proportion of ownership interest in subsidiary   100.00% 84.00%    
AGT Food & Ingredients Inc.          
Total equity          
Value of shares which may be purchased with outstanding warrants       $ 340.0  
Price per share at which equity shares my be purchased with outstanding warrants | $ / shares       $ 22.5  
Borrowings       $ 340.0  
AGT Food & Ingredients Inc. | Proposed initial public offering and secondary offering          
Total equity          
Amount of capital to be raised in public offering $ 449.5        
Equity price per share | $ / shares $ 23        
AGT Food & Ingredients Inc. | Proposed initial public offering          
Total equity          
Amount of capital to be raised in public offering $ 425.0        
AGT Food & Ingredients Inc. | Proposed secondary offering          
Total equity          
Amount of capital to be raised in public offering 24.5        
AGT Food & Ingredients Inc. | Private placement          
Total equity          
Value of shares issued $ 200.0        
Equity price per share | $ / shares $ 23        
Global Insurers and Reinsurers          
Total equity          
Dividends paid   $ 146.3 $ 256.3    
Insurance and reinsurance companies          
Total equity          
Carrying value   3,005.4 2,740.2    
Net earnings (loss) attributable to non-controlling interests   $ 443.5 $ 450.6    
Insurance and reinsurance companies | Allied World          
Total equity          
Economic ownership percentage   16.60% 16.60%    
Carrying value   $ 1,121.7 $ 989.0    
Net earnings (loss) attributable to non-controlling interests   $ 204.5 $ 176.1    
Insurance and reinsurance companies | Odyssey Group          
Total equity          
Economic ownership percentage   9.99% 9.99%    
Carrying value   $ 735.3 $ 665.7    
Net earnings (loss) attributable to non-controlling interests   $ 129.5 $ 128.1    
Insurance and reinsurance companies | KI          
Total equity          
Economic ownership percentage   80.00% 80.00%    
Carrying value   $ 589.7 $ 532.6    
Net earnings (loss) attributable to non-controlling interests   $ 70.6 $ 137.4    
Insurance and reinsurance companies | Gulf Insurance          
Total equity          
Economic ownership percentage   2.90% 2.90%    
Carrying value   $ 496.6 $ 494.1    
Net earnings (loss) attributable to non-controlling interests   27.9 1.7    
Insurance and reinsurance companies | All other          
Total equity          
Carrying value   62.1 58.8    
Net earnings (loss) attributable to non-controlling interests   11.0 7.3    
Non-insurance companies          
Total equity          
Carrying value   1,354.4 1,541.0    
Net earnings (loss) attributable to non-controlling interests   67.9 (62.6)    
Non-insurance companies | Restaurants and retail          
Total equity          
Carrying value   3.3 147.7    
Net earnings (loss) attributable to non-controlling interests   $ 1.4 $ 9.2    
Non-insurance companies | Fairfax India          
Total equity          
Economic ownership percentage   57.10% 57.30%    
Carrying value   $ 1,074.4 $ 1,029.9    
Net earnings (loss) attributable to non-controlling interests   $ 124.0 $ (63.7)    
Non-insurance companies | Thomas Cook India          
Total equity          
Economic ownership percentage   35.50% 35.50%    
Carrying value   $ 99.5 $ 97.1    
Net earnings (loss) attributable to non-controlling interests   12.8 11.7    
Non-insurance companies | All other          
Total equity          
Carrying value   177.2 266.3    
Net earnings (loss) attributable to non-controlling interests   $ (70.3) $ (19.8)