Shareholder's Equity - Change in Shareholders' Equity (Details) - USD ($) $ 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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)			75,300,000				75,300,000
Beginning balance	$ 2,424.4	$ 2,326.2	$ 2,335.4	$ 2,032.6	$ 1,829.0	$ 1,854.5	$ 2,335.4	$ 1,854.5
Net income	120.6	188.5	173.8	175.6	187.3	151.2	$ 482.9	514.1
Activity related to stock-based compensation	$ 15.6	15.1	0.1	16.6	21.8	2.5
Share purchased under share repurchase program (in shares)	86,667						563,334
Shares purchased under share repurchase program	$ (27.2)	(28.6)	(147.1)			(137.1)	$ (202.9)
Dividends declared		(13.3)	(13.2)		(12.5)	(12.5)
Other comprehensive loss, net of tax	$ (62.6)	(63.5)	(22.8)	(22.5)	7.0	(29.6)	$ (148.9)	(45.1)
Ending balance (in shares)	75,300,000						75,300,000
Ending balance	$ 2,470.8	$ 2,424.4	$ 2,326.2	$ 2,202.3	$ 2,032.6	$ 1,829.0	$ 2,470.8	$ 2,202.3
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	75,300,000	75,300,000	75,300,000	75,300,000	75,300,000	75,300,000	75,300,000	75,300,000
Beginning balance	$ 18.8	$ 18.8	$ 18.8	$ 18.8	$ 18.8	$ 18.8	$ 18.8	$ 18.8
Ending balance (in shares)	75,300,000	75,300,000	75,300,000	75,300,000	75,300,000	75,300,000	75,300,000	75,300,000
Ending balance	$ 18.8	$ 18.8	$ 18.8	$ 18.8	$ 18.8	$ 18.8	$ 18.8	$ 18.8
Capital in Excess of Par Value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	225.3	219.9	249.0	248.0	246.7	267.3	249.0	267.3
Activity related to stock-based compensation	5.3	5.4	(29.1)	3.2	1.3	(20.6)
Ending balance	230.6	225.3	219.9	251.2	248.0	246.7	230.6	251.2
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ (366.3)	$ (347.4)	$ (229.5)	$ (261.2)	$ (281.7)	$ (167.7)	$ (229.5)	$ (167.7)
Beginning balance (in shares)	1,300,000	1,200,000	1,100,000	1,300,000	1,500,000	1,300,000	1,100,000	1,300,000
Activity related to stock-based compensation	$ 10.3	$ 9.7	$ 29.2	$ 13.4	$ 20.5	$ 23.1
Activity related to stock -based compensation (in shares)	(100,000)		(300,000)	(100,000)	(200,000)	(300,000)
Share purchased under share repurchase program (in shares)	100,000	100,000	400,000			500,000
Shares purchased under share repurchase program	$ (27.2)	$ (28.6)	$ (147.1)			$ (137.1)
Ending balance	$ (383.2)	$ (366.3)	$ (347.4)	$ (247.8)	$ (261.2)	$ (281.7)	$ (383.2)	$ (247.8)
Ending balance (in shares)	1,300,000	1,300,000	1,200,000	1,200,000	1,300,000	1,500,000	1,300,000	1,200,000
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 2,792.5	$ 2,617.3	$ 2,456.7	$ 2,160.2	$ 1,985.4	$ 1,846.7	$ 2,456.7	$ 1,846.7
Net income	120.6	188.5	173.8	175.6	187.3	151.2
Dividends declared		(13.3)	(13.2)		(12.5)	(12.5)
Ending balance	2,913.1	2,792.5	2,617.3	2,335.8	2,160.2	1,985.4	2,913.1	2,335.8
Accumulated other comprehensive loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(245.9)	(182.4)	(159.6)	(133.2)	(140.2)	(110.6)	(159.6)	(110.6)
Other comprehensive loss, net of tax	(62.6)	(63.5)	(22.8)	(22.5)	7.0	(29.6)
Ending balance	$ (308.5)	$ (245.9)	$ (182.4)	$ (155.7)	$ (133.2)	$ (140.2)	$ (308.5)	$ (155.7)