Corporate Investments and Funds Held for Clients - Schedule of Investment of Funds Held for Clients (Details) - USD ($) $ in Millions	Sep. 30, 2026	Jun. 30, 2026
Debt Securities, Available-for-sale [Line Items]
Restricted cash and cash equivalents held to satisfy client funds obligations	$ 7,406.2	$ 6,395.1
Total funds held for clients	44,733.3	43,957.8
Current
Debt Securities, Available-for-sale [Line Items]
Restricted short-term and long term marketable securities held to satisfy client funds obligations	5,063.2	5,871.3
Non-current
Debt Securities, Available-for-sale [Line Items]
Restricted short-term and long term marketable securities held to satisfy client funds obligations	$ 32,263.9	$ 31,691.4