Corporate Investments and Funds Held For Clients (Expected Maturities Of Available-For-Sale Securities) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Jun. 30, 2020
Corporate Investments And Funds Held For Clients [Abstract]
One year or less	$ 4,778.9
One year to two years	4,561.0
Two years to three years	3,524.7
Three years to four years	2,670.6
After four years	6,815.3
Total available-for-sale securities	$ 22,350.5	$ 21,576.6