Corporate Investments and Funds Held For Clients - Expected Maturities of Available-for-Sale Securities (Details) - USD ($) $ in Millions	Jun. 30, 2025	Jun. 30, 2024
Corporate Investments And Funds Held For Clients [Abstract]
One year or less	$ 7,654.5
One year to two years	5,888.4
Two years to three years	4,322.9
Three years to four years	5,106.0
After four years	10,805.9
Total available-for-sale securities	$ 33,777.7	$ 31,207.5