v3.26.3
Derivative Financial Instruments - Fair Value of Derivatives (Details) - USD ($)
$ in Millions
Sep. 30, 2026
Dec. 31, 2025
Derivatives, fair value disclosures    
Derivative instruments, assets $ 1,803.3 $ 1,224.5
Derivative instruments, liabilities (418.2) (671.2)
Fair value of embedded derivative liabilities reported with contractholder funds 2,432.6 1,410.2
Fair value of net (asset) liability embedded derivative reported with funds withheld payable (3,524.6) (2,633.4)
Derivatives designated as hedging instruments    
Derivatives, fair value disclosures    
Derivative instruments, assets 146.4 144.6
Derivative instruments, liabilities 231.0 208.6
Derivatives not designated as hedging instruments    
Derivatives, fair value disclosures    
Derivative instruments, assets 1,656.9 1,079.9
Derivative instruments, liabilities (649.2) (879.8)
Interest rate contracts | Derivatives designated as hedging instruments    
Derivatives, fair value disclosures    
Derivative instruments, assets 0.1  
Derivative instruments, liabilities 103.6 69.8
Interest rate contracts | Derivatives not designated as hedging instruments    
Derivatives, fair value disclosures    
Derivative instruments, assets 19.5 16.9
Derivative instruments, liabilities 239.8 136.0
Foreign exchange contracts | Derivatives designated as hedging instruments    
Derivatives, fair value disclosures    
Derivative instruments, assets 146.3 144.6
Derivative instruments, liabilities 127.4 138.8
Foreign exchange contracts | Derivatives not designated as hedging instruments    
Derivatives, fair value disclosures    
Derivative instruments, assets 31.7 70.3
Derivative instruments, liabilities 12.7 9.4
Equity contracts | Derivatives not designated as hedging instruments    
Derivatives, fair value disclosures    
Derivative instruments, assets 1,587.2 971.5
Derivative instruments, liabilities 182.1 191.6
Credit contracts | Derivatives not designated as hedging instruments    
Derivatives, fair value disclosures    
Derivative instruments, assets 18.5 21.2
Derivative instruments, liabilities 8.2 6.4
Other contracts | Derivatives not designated as hedging instruments    
Derivatives, fair value disclosures    
Derivative instruments, liabilities $ (1,092.0) $ (1,223.2)