Retirement Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Components of net periodic benefit cost:
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit	$ (2.4)	$ 0.0	$ (2.4)	$ 4.4
Pension Plan [Member]
Components of net periodic benefit cost:
Service cost	3.6	3.4	7.2	6.9
Interest cost	7.6	8.0	15.4	16.0
Expected return on plan assets	(10.2)	(9.7)	(20.5)	(19.4)
Amortization of prior service cost	0.4	0.4	0.8	0.7
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit	(2.4)	0.0	(2.4)	4.4
Net periodic benefit cost	(1.0)	2.1	0.5	8.6
Pension Plan [Member] | Foreign Plan [Member]
Components of net periodic benefit cost:
Service cost	0.4	0.4	0.8	0.8
Interest cost	1.8	1.9	3.7	3.7
Expected return on plan assets	(2.9)	(2.7)	(5.9)	(5.4)
Amortization of prior service cost	0.0	0.0	0.0	0.0
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit	0.0	0.0	0.0	0.0
Net periodic benefit cost	(0.7)	(0.4)	(1.4)	(0.9)
Pension Plan [Member] | Domestic Plan [Member]
Components of net periodic benefit cost:
Service cost	3.2	3.0	6.4	6.1
Interest cost	5.8	6.1	11.7	12.3
Expected return on plan assets	(7.3)	(7.0)	(14.6)	(14.0)
Amortization of prior service cost	0.4	0.4	0.8	0.7
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit	(2.4)	0.0	(2.4)	4.4
Net periodic benefit cost	$ (0.3)	$ 2.5	$ 1.9	$ 9.5