Corporate Investments and Funds Held For Clients (Schedule Of Investment Of Funds Held For Clients) (Details) - USD ($) $ in Millions	Sep. 30, 2021		Jun. 30, 2021	Sep. 30, 2020	[1]
Debt Securities, Available-for-sale [Line Items]
Restricted cash and restricted cash equivalents included in funds held for clients	$ 21,590.2	[1]	$ 10,568.0	$ 8,748.6
Total funds held for clients	46,808.6		34,905.8
Current
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, restricted	4,044.5		3,743.3
Non-current
Debt Securities, Available-for-sale [Line Items]
Available-for-sale securities, restricted	$ 21,173.9		$ 20,594.5

[1] See Note 6 for a reconciliation of restricted cash and restricted cash equivalents in funds held for clients on the Consolidated Balance Sheets.