Goodwill and Acquired Client Relationships - Schedule of Changes in Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Goodwill [Roll Forward]
Balance, beginning of period	$ 2,504.9	$ 2,523.6
Foreign currency translation	26.3	(18.7)
Balance, end of period	$ 2,531.2	$ 2,504.9