Retirement Benefit Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Payment for Pension Benefits	$ 11.5	$ 15.0	$ 10.8
Pension Plan [Member]
Components of net periodic benefit cost:
Defined Benefit Plan, Plan Assets, Payment for Settlement	(23.2)	(60.9)	(21.1)
Foreign Plan [Member] | Pension Plan [Member]
Components of net periodic benefit cost:
Service cost	1.6	1.4	2.2
Interest cost	7.5	10.5	12.3
Expected return on plan assets	(11.1)	(10.7)	(18.2)
Amortization of prior service cost	0.0	0.1	0.1
Defined Benefit Plan, Plan Assets, Payment for Settlement	0.1	19.4	(17.7)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	0.0	0.0	0.0
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	0.0	(0.1)	0.6
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	0.0	0.0	0.6
Net periodic benefit cost	(1.9)	20.6	(20.1)
Domestic Plan [Member] | Pension Plan [Member]
Components of net periodic benefit cost:
Service cost	12.2	13.1	15.4
Interest cost	24.6	26.6	45.6
Expected return on plan assets	(28.0)	(30.1)	(66.9)
Amortization of prior service cost	1.4	1.7	2.8
Defined Benefit Plan, Plan Assets, Payment for Settlement	23.1	41.5	(3.4)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement	0.0	0.0	116.1
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment	(1.1)	0.0	0.0
Defined Benefit Plan, Benefit Obligation, Special and Contractual Termination Benefits	0.0	0.0	0.0
Net periodic benefit cost	$ 32.2	$ 52.8	$ 109.6