Corporate Investments and Funds Held for Clients - Schedule of Expected Maturities of Available-For-Sale Securities (Details) - USD ($) $ in Millions	Dec. 31, 2025	Jun. 30, 2025
Investments, Debt and Equity Securities [Abstract]
One year or less	$ 7,630.4
One year to two years	4,675.5
Two years to three years	6,606.4
Three years to four years	5,167.3
After four years	12,239.2
Total available-for-sale securities	$ 36,318.8	$ 33,777.7