Corporate Investments and Funds Held for Clients - Schedule of Investment of Funds Held for Clients (Details) - USD ($) $ in Millions	Dec. 31, 2024		Jun. 30, 2024	Dec. 31, 2023	[1]
Debt Securities, Available-for-sale [Line Items]
Restricted cash and cash equivalents held to satisfy client funds obligations	$ 14,387.8	[1]	$ 7,172.6	$ 12,238.0
Total funds held for clients	47,407.7		37,996.1
Current
Debt Securities, Available-for-sale [Line Items]
Restricted short-term and long term marketable securities held to satisfy client funds obligations	6,807.9		5,538.1
Non-current
Debt Securities, Available-for-sale [Line Items]
Restricted short-term and long term marketable securities held to satisfy client funds obligations	$ 26,212.0		$ 25,285.4

[1] See Note 7 for a reconciliation of restricted cash and restricted cash equivalents in funds held for clients on the Consolidated Balance Sheets.