v3.10.0.1
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