CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 147.1	$ 181.4
Other comprehensive income:
Change in fair value of cash flow swaps	10.0	(19.4)
Income tax (expense) benefit associated with cash flow swaps	(2.5)	4.7
Unrealized (losses) gains on available-for-sale debt securities	(2.8)	2.5
Income tax benefit (expense) associated with available-for-sale debt securities	0.6	(0.5)
Comprehensive income	$ 152.4	$ 168.7