Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Accumulated Other Comprehensive Income	Retained Earnings (Accumulated Deficit)
Balance, shares at Dec. 31, 2020		133.1
Balance at Dec. 31, 2020	$ 5,655.1	$ 7,118.2	$ 395.0	$ (1,858.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(68.9)			(68.9)
Other comprehensive income (loss)	(359.5)		(359.5)
Issuance of ordinary shares under:
Restricted stock plan, shares		1.0
Compensation for stock options	0.9	$ 0.9
Compensation for restricted stock	66.9	66.9
Cash dividends	(129.6)	$ (129.6)
Shares withheld for payment of employees' withholding tax liability, shares		(0.3)
Shares withheld for payment of employees' withholding tax liability	(13.2)	$ (13.2)
Balance, shares at Dec. 31, 2021		133.8
Balance at Dec. 31, 2021	5,151.7	$ 7,043.2	35.5	(1,927.0)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(140.6)			(140.6)
Other comprehensive income (loss)	(62.5)		(62.5)
Issuance of ordinary shares under:
Restricted stock plan, shares		1.4
Compensation for restricted stock	54.9	$ 54.9
Cash dividends	(142.4)	$ (142.4)
Shares withheld for payment of employees' withholding tax liability, shares		(0.5)
Shares withheld for payment of employees' withholding tax liability	(19.0)	$ (19.0)
Balance, shares at Dec. 31, 2022		134.7
Balance at Dec. 31, 2022	4,842.1	$ 6,936.7	(27.0)	(2,067.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(12.7)			(12.7)
Other comprehensive income (loss)	37.7		37.7
Issuance of ordinary shares under:
Restricted stock plan, shares		1.3
Compensation for restricted stock	68.8	$ 68.8
Cash dividends	(149.7)	$ (149.7)
Shares withheld for payment of employees' withholding tax liability, shares		(0.5)
Shares withheld for payment of employees' withholding tax liability	(18.3)	$ (18.3)
Balance, shares at Dec. 31, 2023		135.5
Balance at Dec. 31, 2023	$ 4,767.9	$ 6,837.5	$ 10.7	$ (2,080.3)