v3.25.4
Financial Risk Management - Market Risk - Interest rate risk (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Financial Risk Management    
Amount of bonds $ 39,988.8 $ 37,390.3
Eurolife Life Operations    
Financial Risk Management    
Amount of bonds 1,403.8  
200 basis point increase    
Financial Risk Management    
Liability for incurred claims, net of reinsurance 34,179.9 30,794.9
Hypothetical change in net earnings 1,468.9 1,324.2
100 basis point increase    
Financial Risk Management    
Liability for incurred claims, net of reinsurance 35,074.7 31,594.1
Hypothetical change in net earnings 760.7 686.2
No change    
Financial Risk Management    
Liability for incurred claims, net of reinsurance 36,035.5 32,453.7
100 basis point decrease    
Financial Risk Management    
Liability for incurred claims, net of reinsurance 37,070.9 33,381.8
Hypothetical change in net earnings (819.8) (741.0)
200 basis point decrease    
Financial Risk Management    
Liability for incurred claims, net of reinsurance 38,191.1 34,387.9
Hypothetical change in net earnings (1,706.8) (1,544.4)
Interest rate risk    
Financial Risk Management    
Fixed income securities 40,800.0 38,200.0
Liability for incurred claims, net of reinsurance 36,035.5 32,453.7
Interest rate risk | Investments in debt instruments | Eurolife Life Operations    
Financial Risk Management    
Amount of bonds 1,403.8  
Interest rate risk | Forward contracts to sell long-dated U.S. treasury bonds    
Financial Risk Management    
Notional amount 246.6 0.0
Interest rate risk | Forward contracts to buy long-dated U.S. treasury bonds    
Financial Risk Management    
Notional amount   1,330.2
Interest rate risk | U.S. treasury bond forward contracts    
Financial Risk Management    
Notional amount 0.0 1,330.2
Interest rate risk | Interest rate swaps    
Financial Risk Management    
Notional amount 0.0 1,900.0
Interest rate risk | 200 basis point increase    
Financial Risk Management    
Fair value of fixed income portfolio 38,838.3 35,484.7
Hypothetical change in net earnings $ (1,535.6) $ (2,209.6)
Hypothetical % change in fair value (4.70%) (7.20%)
Interest rate risk | 100 basis point increase    
Financial Risk Management    
Fair value of fixed income portfolio $ 39,779.3 $ 36,801.1
Hypothetical change in net earnings $ (783.1) $ (1,152.1)
Hypothetical % change in fair value (2.40%) (3.80%)
Interest rate risk | No change    
Financial Risk Management    
Fair value of fixed income portfolio $ 40,758.7 $ 38,235.5
Interest rate risk | 100 basis point decrease    
Financial Risk Management    
Fair value of fixed income portfolio 41,776.9 39,791.1
Hypothetical change in net earnings $ 814.8 $ 1,250.2
Hypothetical % change in fair value 2.50% 4.10%
Interest rate risk | 200 basis point decrease    
Financial Risk Management    
Fair value of fixed income portfolio $ 42,839.1 $ 41,539.4
Hypothetical change in net earnings $ 1,664.4 $ 2,654.3
Hypothetical % change in fair value 5.10% 8.60%
Equity price risk | Forward contracts to buy long-dated U.S. treasury bonds    
Financial Risk Management    
Notional amount   $ 1,330.2
Equity price risk | Interest rate swaps    
Financial Risk Management    
Notional amount   $ 1,900.0