Defined Benefit Pension Plans and Other Post-Employment Benefit Plans - Components of Net Periodic Benefit Cost (Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Components of net periodic benefit cost (income):
Service cost	$ 1.0	$ 1.7	$ 3.2	$ 5.2
Interest cost	5.5	5.6	16.5	17.1
Expected return on plan assets	(9.6)	(10.0)	(28.9)	(30.1)
Amortization of net actuarial loss	0.9	1.6	2.6	4.8
Net periodic (income) benefit cost	(2.2)	(1.1)	(6.6)	(3.0)
Cost (income) of settlement/curtailment	1.6	1.3	1.7	2.6
Total benefit cost (income)	(0.6)	0.2	(4.9)	(0.4)
U.S.
Components of net periodic benefit cost (income):
Service cost	0.0	0.0	0.1	0.1
Interest cost	1.6	1.6	4.8	5.1
Expected return on plan assets	(2.2)	(2.4)	(6.6)	(7.3)
Amortization of net actuarial loss	0.3	0.2	0.7	0.6
Net periodic (income) benefit cost	(0.3)	(0.6)	(1.0)	(1.5)
Cost (income) of settlement/curtailment	1.4	0.4	1.4	1.2
Total benefit cost (income)	1.1	(0.2)	0.4	(0.3)
International
Components of net periodic benefit cost (income):
Service cost	1.0	1.7	3.1	5.1
Interest cost	3.9	4.0	11.7	12.0
Expected return on plan assets	(7.4)	(7.6)	(22.3)	(22.8)
Amortization of net actuarial loss	0.6	1.4	1.9	4.2
Net periodic (income) benefit cost	(1.9)	(0.5)	(5.6)	(1.5)
Cost (income) of settlement/curtailment	0.2	0.9	0.3	1.4
Total benefit cost (income)	(1.7)	0.4	(5.3)	(0.1)
Other employee benefit plans
Components of net periodic benefit cost (income):
Service cost	0.0	0.0	0.0	0.1
Interest cost	0.4	0.4	1.1	1.3
Amortization of net prior service cost	0.0	(0.3)	(0.2)	(1.1)
Amortization of net actuarial loss	0.0	0.0	(0.1)	(0.1)
Net periodic (income) benefit cost	0.4	0.1	0.8	0.2
Cost (income) of settlement/curtailment	0.0	(13.5)	0.0	(13.5)
Total benefit cost (income)	$ 0.4	$ (13.4)	$ 0.8	$ (13.3)