v3.25.4
Segmented Information - Geographic Region (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Segmented Information    
Insurance revenue $ 31,595.0 $ 31,064.1
Distribution of insurance revenue 100.00% 100.00%
Canada    
Segmented Information    
Insurance revenue $ 2,796.7 $ 2,869.1
Distribution of insurance revenue 8.90% 9.20%
United States    
Segmented Information    
Insurance revenue $ 18,143.5 $ 17,167.6
Distribution of insurance revenue 57.40% 55.30%
Middle East and Asia    
Segmented Information    
Insurance revenue $ 4,401.0 $ 5,249.5
Distribution of insurance revenue 13.90% 16.90%
Other International    
Segmented Information    
Insurance revenue $ 6,253.8 $ 5,777.9
Distribution of insurance revenue 19.80% 18.60%
Property and Casualty Insurance and Reinsurance    
Segmented Information    
Insurance revenue $ 31,341.7 $ 30,874.5
Property and Casualty Insurance and Reinsurance | Canada    
Segmented Information    
Insurance revenue 2,796.7 2,869.1
Property and Casualty Insurance and Reinsurance | United States    
Segmented Information    
Insurance revenue 18,106.8 17,156.7
Property and Casualty Insurance and Reinsurance | Middle East and Asia    
Segmented Information    
Insurance revenue 4,341.1 5,207.5
Property and Casualty Insurance and Reinsurance | Other International    
Segmented Information    
Insurance revenue 6,097.1 5,641.2
Property and Casualty Insurance and Reinsurance | North American Insurers    
Segmented Information    
Insurance revenue 9,150.2 8,731.8
Property and Casualty Insurance and Reinsurance | North American Insurers | Canada    
Segmented Information    
Insurance revenue 2,403.0 2,441.7
Property and Casualty Insurance and Reinsurance | North American Insurers | United States    
Segmented Information    
Insurance revenue 6,707.4 6,240.3
Property and Casualty Insurance and Reinsurance | North American Insurers | Middle East and Asia    
Segmented Information    
Insurance revenue 2.5 3.7
Property and Casualty Insurance and Reinsurance | North American Insurers | Other International    
Segmented Information    
Insurance revenue 37.3 46.1
Property and Casualty Insurance and Reinsurance | Global Insurers and Reinsurers    
Segmented Information    
Insurance revenue 16,222.0 15,513.0
Property and Casualty Insurance and Reinsurance | Global Insurers and Reinsurers | Canada    
Segmented Information    
Insurance revenue 393.1 427.1
Property and Casualty Insurance and Reinsurance | Global Insurers and Reinsurers | United States    
Segmented Information    
Insurance revenue 11,398.3 10,912.7
Property and Casualty Insurance and Reinsurance | Global Insurers and Reinsurers | Middle East and Asia    
Segmented Information    
Insurance revenue 956.0 945.2
Property and Casualty Insurance and Reinsurance | Global Insurers and Reinsurers | Other International    
Segmented Information    
Insurance revenue 3,474.6 3,228.0
Property and Casualty Insurance and Reinsurance | International Insurers and Reinsurers    
Segmented Information    
Insurance revenue 5,969.5 6,629.7
Property and Casualty Insurance and Reinsurance | International Insurers and Reinsurers | Canada    
Segmented Information    
Insurance revenue 0.6 0.3
Property and Casualty Insurance and Reinsurance | International Insurers and Reinsurers | United States    
Segmented Information    
Insurance revenue 1.1 3.7
Property and Casualty Insurance and Reinsurance | International Insurers and Reinsurers | Middle East and Asia    
Segmented Information    
Insurance revenue 3,382.6 4,258.6
Property and Casualty Insurance and Reinsurance | International Insurers and Reinsurers | Other International    
Segmented Information    
Insurance revenue 2,585.2 2,367.1
Life insurance and Run-off    
Segmented Information    
Insurance revenue 253.3 189.6
Life insurance and Run-off | United States    
Segmented Information    
Insurance revenue 36.7 10.9
Life insurance and Run-off | Middle East and Asia    
Segmented Information    
Insurance revenue 59.9 42.0
Life insurance and Run-off | Other International    
Segmented Information    
Insurance revenue $ 156.7 $ 136.7