Corporate Investments And Funds Held For Clients (Expected Maturities Of Available-For-Sale Securities) (Details) $ in Millions	Dec. 31, 2015 USD ($)
Corporate Investments And Funds Held For Clients [Abstract]
One year or less	$ 3,623.4
One year to two years	3,037.6
Two years to three years	2,213.8
Three years to four years	3,814.9
After four years	7,595.4
Total available-for-sale securities	$ 20,285.1