Net Income Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Earnings Per Share [Abstract]
Net income	$ 120.6	$ 188.5	$ 173.8	$ 175.6	$ 187.3	$ 151.2	$ 482.9	$ 514.1
Weighted average common shares outstanding (in shares)	74,400,000			74,100,000			74,400,000	74,000,000.0
Dilutive effect of equity awards, based on the treasury stock method (in shares)	1,300,000			1,900,000			1,500,000	1,800,000
Weighted average shares assuming dilution (in shares)	75,700,000			76,000,000.0			75,900,000	75,800,000
Antidilutive options excluded from computation of diluted net income per share (in shares)	200,000			0			100,000	0
Stock repurchase program, shares authorized (in shares)									650,000
Share purchased under share repurchase program (in shares)	86,667						563,334
Stock purchase program, cost of shares purchased	$ 27.2	$ 28.6	$ 147.1			$ 137.1	$ 202.9
Stock repurchase program, average price per share (in dollars per share)	$ 313.22						$ 360.03