Corporate Investments and Funds Held For Clients - Summary of Unrealized Losses and Fair Values of Available-for-Sale Securities that have been in Unrealized Loss Position for Period of Less than and Greater than 12 Months (Details) - Available-for-sale Securities [Member] $ in Millions	Jun. 30, 2026 USD ($)
Corporate Investments And Funds Held For Clients [Line Items]
Securities in unrealized loss position for less than 12 months, Gross unrealized losses	$ (0.2)
Securities in unrealized loss position for less than 12 months, Fair value	241.2
Gross unrealized losses	(0.2)
Fair value	241.2
U.S. Treasury Securities [Member]
Corporate Investments And Funds Held For Clients [Line Items]
Securities in unrealized loss position for less than 12 months, Gross unrealized losses	(0.2)
Securities in unrealized loss position for less than 12 months, Fair value	241.2
Gross unrealized losses	(0.2)
Fair value	241.2
Certificates of Deposit [Member]
Corporate Investments And Funds Held For Clients [Line Items]
Securities in unrealized loss position for less than 12 months, Fair value	75.0
Fair value	$ 75.0

Corporate Investments and Funds Held For Clients - Summary of Unrealized Losses and Fair Values of Available-for-Sale Securities that have been in Unrealized Loss Position for Period of Less than and Greater than 12 Months (Details) - Available-for-sale Securities [Member]
$ in Millions

Jun. 30, 2026

USD ($)

Corporate Investments And Funds Held For Clients [Line Items]

Securities in unrealized loss position for less than 12 months, Gross unrealized losses

$ (0.2)

Securities in unrealized loss position for less than 12 months, Fair value

241.2

Gross unrealized losses

(0.2)

Fair value

241.2

U.S. Treasury Securities [Member]