Corporate Investments and Funds Held For Clients (Classification Of Corporate Investments On The Consolidated Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Corporate Investments And Funds Held For Clients [Abstract]
Cash and cash equivalents	$ 2,705.2	$ 3,191.1	$ 2,794.9	$ 1,639.3
Short-term marketable securities	41.0	23.5
Long-term marketable securities	7.6	7.8
Total corporate investments	$ 2,753.8	$ 3,222.4