Pension and Other Postretirement Benefits - Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Selling, General and Administrative Expense	$ 273.5	$ 263.3
Non-operating Expense	6.6	7.5
Pension Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Service cost	6.5	7.1
Selling, General and Administrative Expense	6.5	7.1
Interest cost	7.6	7.0
Expected return on plan assets	(8.6)	(8.1)
Amortization of: Net actuarial loss	4.9	6.7
Amortization of: Prior service cost (gain)	0.0	0.1
Non-operating Expense	3.9	5.7
Net periodic benefit cost	10.4	12.8
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Service cost	0.5	0.6
Selling, General and Administrative Expense	0.5	0.6
Interest cost	0.8	0.7
Expected return on plan assets	0.0	0.0
Amortization of: Net actuarial loss	0.1	0.2
Amortization of: Prior service cost (gain)	0.0	(0.5)
Non-operating Expense	0.9	0.4
Net periodic benefit cost	$ 1.4	$ 1.0