Retirement Benefit Plans - Change in Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in plan assets:
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 35.4	$ 11.3	$ 11.5
Pension Plan [Member]
Change in plan assets:
Defined Benefit Plan, Plan Assets, Contributions by Employer	35.4	11.3
Defined Benefit Plan, Plan Assets, Business Combination	0.0	44.4
UNITED STATES | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Company contributions / payments	104.2	(37.5)
Change in plan assets:
Fair value of plan assets at beginning of year	448.3	531.9
Defined Benefit Plan, Plan Assets, Contributions by Employer	28.7	5.3
International plan exchange rate change	0.0	0.0
Benefits paid	(61.0)	(95.8)
Fair value of plan assets at end of year	520.2	448.3	531.9
Funded status at end of year	(114.5)	(138.3)
Foreign Plan [Member]
Change in plan assets:
Defined Benefit Plan, Plan Assets, Business Combination	0.0	1.5
Foreign Plan [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Company contributions / payments	21.9	(5.1)
Change in plan assets:
Fair value of plan assets at beginning of year	254.6	292.4
Defined Benefit Plan, Plan Assets, Contributions by Employer	6.7	6.0
International plan exchange rate change	8.9	(15.4)
Benefits paid	(17.4)	(24.8)
Fair value of plan assets at end of year	274.7	254.6	$ 292.4
Funded status at end of year	$ (54.1)	$ (45.7)