Corporate Investments And Funds Held For Clients (Expected Maturities Of Available-For-Sale Securities) (Details) $ in Millions	Sep. 30, 2016 USD ($)
Corporate Investments And Funds Held For Clients [Abstract]
One year or less	$ 3,178.2
One year to two years	2,525.4
Two years to three years	4,039.2
Three years to four years	4,486.9
After four years	7,521.3
Total available-for-sale securities	$ 21,751.0