Corporate Investments and Funds Held for Clients - Expected Maturities of Available-For-Sale Securities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Jun. 30, 2023
Corporate Investments And Funds Held For Clients [Abstract]
One year or less	$ 5,652.6
One year to two years	8,272.1
Two years to three years	5,832.8
Three years to four years	2,768.5
After four years	8,570.4
Total available-for-sale securities	$ 31,096.4	$ 29,764.9