Other Information (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Cash Flow Information and Other Information [Abstract]
Unbilled receivables included in receivables	$ 638.4	$ 804.3
Trading securities included in investments	28.4	35.8
Net capitalized software costs included in other assets	$ 60.1	$ 57.3