Consolidated Statements Of Comprehensive Income (Parenthetical) (Unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Other comprehensive income/(loss), tax	$ 8.7	$ 20.8
Reclassifications to earnings of realized gains/(losses) on available-for-sale securities	$ 5.6	$ 0.0