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, 2020		65.4
Beginning balance at Dec. 31, 2020	$ 4,563.4	$ 6.5	$ 1,805.2	$ 2,071.2	$ 680.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	60.6			60.6
Other Comprehensive Income (Loss), Net of Tax	$ (137.5)				(137.5)
Dividends paid to shareholders per share (in dollars per share)	$ 0.62
Cash Dividends and Dividend Equivalents to Shareholders	$ (41.4)			(41.4)
Repurchases of Common Stock (in shares)		2.0
Repurchases of Common Stock (Note 10)	(158.7)	$ (0.2)	(56.7)	(101.8)
Shares Issued Under Employee Stock Purchase Plan (Note 10)			2.5
Shares Issued Under Employee Stock Purchase Plan (Note 10)	2.5
Equity-based Compensation Cost	18.5		18.5
Equity-based Awards, Net of Shares Exchanged (in shares)		0.2
Equity-based Awards, Net of Shares Exchanged	(1.2)	$ 0.1	1.4	(2.7)
Ending balance (in shares) at Jun. 30, 2021		63.6
Ending balance at Jun. 30, 2021	4,306.2	$ 6.4	1,770.9	1,985.9	543.0
Beginning balance (in shares) at Mar. 31, 2021		65.0
Beginning balance at Mar. 31, 2021	4,339.1	$ 6.5	1,802.1	2,140.0	390.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(62.6)			(62.6)
Other Comprehensive Income (Loss), Net of Tax	$ 152.5				152.5
Dividends paid to shareholders per share (in dollars per share)	$ 0.31
Cash Dividends and Dividend Equivalents to Shareholders	$ (20.4)			(20.4)
Repurchases of Common Stock (in shares)		1.4
Repurchases of Common Stock (Note 10)	(111.6)	$ (0.2)	(40.3)	(71.1)
Shares Issued Under Employee Stock Purchase Plan (Note 10)			1.3
Shares Issued Under Employee Stock Purchase Plan (Note 10)	1.3
Equity-based Compensation Cost	6.2		6.2
Equity-based Awards, Net of Shares Exchanged (in shares)		0.0
Equity-based Awards, Net of Shares Exchanged	1.7	$ 0.1	1.6	0.0
Ending balance (in shares) at Jun. 30, 2021		63.6
Ending balance at Jun. 30, 2021	4,306.2	$ 6.4	1,770.9	1,985.9	543.0
Beginning balance (in shares) at Dec. 31, 2021		63.7
Beginning balance at Dec. 31, 2021	4,007.7	$ 6.4	1,790.7	1,762.5	448.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(169.5)			(169.5)
Other Comprehensive Income (Loss), Net of Tax	$ (968.9)				(968.9)
Dividends paid to shareholders per share (in dollars per share)	$ 0.62
Cash Dividends and Dividend Equivalents to Shareholders	$ (40.2)			(40.2)
Shares Issued Under Employee Stock Purchase Plan (Note 10)		$ 0.0	2.5
Shares Issued Under Employee Stock Purchase Plan (Note 10)	2.5
Equity-based Compensation Cost	20.2		20.2
Equity-based Awards, Net of Shares Exchanged (in shares)		0.1
Equity-based Awards, Net of Shares Exchanged	(1.8)	$ 0.0	(0.9)	(0.9)
Ending balance (in shares) at Jun. 30, 2022		63.8
Ending balance at Jun. 30, 2022	2,850.0	$ 6.4	1,812.5	1,551.9	(520.8)
Beginning balance (in shares) at Mar. 31, 2022		63.8
Beginning balance at Mar. 31, 2022	3,394.5	$ 6.4	1,803.1	1,647.3	(62.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(74.7)			(74.7)
Other Comprehensive Income (Loss), Net of Tax	$ (458.5)				(458.5)
Dividends paid to shareholders per share (in dollars per share)	$ 0.31
Cash Dividends and Dividend Equivalents to Shareholders	$ (20.6)			(20.6)
Shares Issued Under Employee Stock Purchase Plan (Note 10)		$ 0.0	1.2
Shares Issued Under Employee Stock Purchase Plan (Note 10)	1.2
Equity-based Compensation Cost	8.3		8.3
Equity-based Awards, Net of Shares Exchanged (in shares)		0.0
Equity-based Awards, Net of Shares Exchanged	(0.2)	$ 0.0	(0.1)	(0.1)
Ending balance (in shares) at Jun. 30, 2022		63.8
Ending balance at Jun. 30, 2022	$ 2,850.0	$ 6.4	$ 1,812.5	$ 1,551.9	$ (520.8)