Pension and Other Postemployment Benefits (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Pension Plans [Member]
Components of Net Periodic Benefit Expense
Service cost	$ 6.4	$ 7.8
Interest cost	5.1	5.4
Expected return on plan assets	(1.8)	(2.2)
Amortization of prior service cost	3.3	3.5
Amortization of actuarial losses	4.9	4.8
Net periodic benefit expense	17.9	19.3
Employer contributions	1.3	1.1
Postemployment Arrangements [Member]
Components of Net Periodic Benefit Expense
Service cost	3.6	3.3
Interest cost	2.7	2.8
Amortization of prior service cost	2.6	2.6
Amortization of actuarial losses	1.3	0.8
Net periodic benefit expense	$ 10.2	$ 9.5