Corporate Investments and Funds Held For Clients (Schedule Of Investment Of Funds Held For Clients) (Details) - USD ($) $ in Millions	Dec. 31, 2018		Jun. 30, 2018	Dec. 31, 2017	[1]
Corporate Investments And Funds Held For Clients [Abstract]
Restricted cash and cash equivalents held to satisfy client funds obligations	$ 2,698.4	[1]	$ 4,372.1	$ 12,086.4
Restricted short-term marketable securities held to satisfy client funds obligations	3,773.5		2,521.4
Restricted long-term marketable securities held to satisfy client funds obligations	19,134.0		20,244.3
Total funds held for clients	$ 25,605.9		$ 27,137.8

[1] See Note 8 for a reconciliation of restricted cash and restricted cash equivalents in funds held for clients on the Consolidated Balance Sheets.