Equity (Components of Shareholders' Equity Rollforward) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 760.4	$ 654.0
Net earnings	0.5	80.3
Other comprehensive income (loss), net of tax	(33.4)	(14.7)
Share-based compensation activity	12.2	7.1
Dividends to ordinary shareholders	$ (29.6)	$ (25.5)
Ordinary shares, Dividends per share (in dollars per share)	$ 0.32	$ 0.27
Repurchase of ordinary shares	$ (94.1)	$ (63.8)
Ending balance	613.8	637.4
Accounting Standards Update 2016-13
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption of ASC 326 (see Note 2)	(2.2)
Ordinary shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 0.9	$ 0.9
Beginning balance (in shares)	92.7	94.6
Share-based compensation activity	$ 0.0	$ 0.0
Share-based compensation activity, shares (in shares)	0.4	0.2
Repurchase of ordinary shares	$ 0.0	$ 0.0
Repurchase of ordinary shares (in shares)	(0.9)	(0.7)
Ending balance	$ 0.9	$ 0.9
Ending balance (in shares)	92.2	94.1
Capital in excess of par value
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 0.0	$ 0.0
Share-based compensation activity	12.2	7.1
Repurchase of ordinary shares	(12.2)	(7.1)
Ending balance	0.0	0.0
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	975.1	873.6
Net earnings	0.4	80.2
Dividends to ordinary shareholders	(29.6)	(25.5)
Repurchase of ordinary shares	(81.9)	(56.7)
Ending balance	861.8	871.6
Retained earnings \| Accounting Standards Update 2016-13
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption of ASC 326 (see Note 2)	(2.2)
Accumulated other comprehensive loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(218.6)	(223.5)
Other comprehensive income (loss), net of tax	(32.8)	(15.3)
Ending balance	(251.4)	(238.8)
Noncontrolling interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	3.0	3.0
Net earnings	0.1	0.1
Other comprehensive income (loss), net of tax	(0.6)	0.6
Ending balance	$ 2.5	$ 3.7

Amount of increase to additional paid-in capital (APIC) for recognition of cost for award under share-based payment arrangement.

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