Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, income tax (benefit) expense	$ (16.0)	$ 1.2	$ (33.5)
Unrealized gains on Fortitude Re available-for-sale securities, income tax (benefit) expense			(5.3)
Unrealized loss for the period, income tax (benefit) expense	4.6	2.9	(2.3)
Reclassification adjustment for unrecognized gain during the period included in base compensation expense, income tax (benefit) expense	$ 0.3	$ 0.7	$ 0.6