Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Statement of Comprehensive Income [Abstract]
Net income	$ 888.8	$ 665.4	$ 1,702.6	$ 1,303.1
Other comprehensive income (loss), net of tax:
Change in foreign currency translation	2.4	(1.0)	3.1	(2.4)
Available-for-sale investments:
Change in net unrealized gains (losses) on available-for-sale securities	3.3	(2.1)	13.9	(9.3)
Other comprehensive income (loss)	5.7	(3.1)	17.0	(11.7)
Comprehensive income	$ 894.5	$ 662.3	$ 1,719.6	$ 1,291.4