Consolidated Statements of Shareholders’ Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income
Beginning balance (in shares) at Dec. 31, 2018		64.7
Beginning balance at Dec. 31, 2018	$ 3,050.1	$ 6.5	$ 1,666.3	$ 1,355.5	$ 21.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	155.3			155.3
Other Comprehensive Loss (Note 8)	129.1				129.1
Cash Dividends and Dividend Equivalents to Shareholders	(16.4)			(16.4)
Equity-based Compensation Cost	7.6		7.6
Equity-based Awards, Net of Shares Exchanged (in shares)		0.2
Equity-based Awards, Net of Shares Exchanged	(5.6)	$ 0.0	(0.9)	(4.7)	0.0
Ending balance (in shares) at Mar. 31, 2019		64.9
Ending balance at Mar. 31, 2019	3,320.1	$ 6.5	1,673.0	1,489.7	150.9
Beginning balance (in shares) at Dec. 31, 2019		66.7
Beginning balance at Dec. 31, 2019	3,972.3	$ 6.7	1,819.2	1,810.3	336.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	64.0			64.0
Other Comprehensive Loss (Note 8)	(161.2)				(161.2)
Cash Dividends and Dividend Equivalents to Shareholders	$ (20.2)			(20.2)
Repurchases of Common Stock (in shares)	(1.5)	(1.5)
Repurchases of Common Stock	$ (101.2)	$ (0.1)	(40.7)	(60.4)
Shares Issued Under Employee Stock Purchase Plan	1.0		1.0
Equity-based Compensation Cost	7.3		7.3
Equity-based Awards, Net of Shares Exchanged (in shares)		0.2
Equity-based Awards, Net of Shares Exchanged	(1.2)	$ (0.1)	1.4	(2.5)
Ending balance (in shares) at Mar. 31, 2020		65.4
Ending balance at Mar. 31, 2020	$ 3,760.8	$ 6.5	$ 1,788.2	$ 1,791.2	$ 174.9