Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Millions	Total	Common stock [Member]	Treasury Stock, Common	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period, Shares			32,700,000
Dividends Declared [Table Text Block]	2.00
Balance at beginning of year at Dec. 31, 2020		67,800,000
Balance at beginning of period, Common Stock at Dec. 31, 2020		$ 41.9
Balance at beginning of period at Dec. 31, 2020			$ (1,364.5)	$ 735.4	$ 2,682.1	$ (137.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock, Shares		500,000
Issuance of common stock		$ 0.3
Stock repurchases, Shares	131,300
Share-based compensation effects				28.4
Net income	$ 143.1
Dividends declared per share ($2.20 in 2023, $2.08 in 2022 and $2.00 in 2021)					73.7
Other comprehensive income (loss)	(23.1)
Balance at end of period, Common Stock, Shares at Dec. 31, 2021		68,300,000
Balance at end of period, Common Stock at Dec. 31, 2021		$ 42.2
Balance at end of period at Dec. 31, 2021	2,019.2		$ (1,377.7)	763.8	2,751.5	(160.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Repurchased During Period, Value	$ 13.2
Balance at beginning of period, Shares			32,800,000
Dividends Declared [Table Text Block]	2.08
Issuance of common stock, Shares		300,000
Issuance of common stock		$ 0.2
Stock repurchases, Shares	472,609
Share-based compensation effects				28.4
Net income	$ 155.9
Dividends declared per share ($2.20 in 2023, $2.08 in 2022 and $2.00 in 2021)					75.9
Other comprehensive income (loss)	$ (51.0)
Balance at end of period, Common Stock, Shares at Dec. 31, 2022	68,575,974	68,600,000
Balance at end of period, Common Stock at Dec. 31, 2022	$ 42.4	$ 42.4
Balance at end of period at Dec. 31, 2022	2,029.6		$ (1,424.9)	792.2	2,831.5	(211.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Repurchased During Period, Value	$ 47.2
Balance at beginning of period, Shares			33,300,000
Dividends Declared [Table Text Block]	2.20
Issuance of common stock, Shares		200,000
Issuance of common stock		$ 0.1
Stock repurchases, Shares	24,520
Share-based compensation effects				23.9
Net income	$ 259.2
Dividends declared per share ($2.20 in 2023, $2.08 in 2022 and $2.00 in 2021)					81.2
Other comprehensive income (loss)	$ 44.0
Balance at end of period, Common Stock, Shares at Dec. 31, 2023	68,797,027	68,800,000
Balance at end of period, Common Stock at Dec. 31, 2023	$ 42.5	$ 42.5
Balance at end of period at Dec. 31, 2023	2,273.0		$ (1,427.5)	$ 816.1	$ 3,009.5	$ (167.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Repurchased During Period, Value	$ 2.6
Balance at beginning of period, Shares			33,300,000