Quarterly report [Sections 13 or 15(d)]

Funds Held for Clients and Corporate Investments (Amortized Cost and Fair Value of Available-for-Sale Securities by Contractual Maturity) (Details)

v3.25.2
Funds Held for Clients and Corporate Investments (Amortized Cost and Fair Value of Available-for-Sale Securities by Contractual Maturity) (Details) - USD ($)
$ in Millions
Aug. 31, 2025
May 31, 2025
Funds Held for Clients and Corporate Investments [Abstract]    
Due in one year or less, Amortized cost $ 677.9  
Due after one year through three years, Amortized cost 2,104.8  
Due after three years through five years, Amortized cost 645.9  
Due after five years, Amortized cost 1,569.2  
AFS securities, Amortized cost 4,997.8 $ 3,809.1
Due in one year or less, Fair value 672.2  
Due after one year through three years, Fair value 2,078.7  
Due after three years through five years, Fair value 650.2  
Due after five years, Fair value 1,575.7  
AFS securities, Fair value $ 4,976.8 $ 3,755.5