Retirement and Other Postretirement Benefit Plans - Schedule of Pension Assets Measured at Fair Value (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	$ 184.3	$ 201.8
Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	44.4	56.3
Diversified Growth Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	44.5	48.0
Liability Driven Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	31.7	38.7
Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	4.2	4.2
Index Linked Gilts
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	57.0	52.1
Diversified Investment, Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	2.0	2.3
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	0.5	0.2
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	0.5	0.2
Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	0.5	0.2
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	177.6	195.1
Level 2 | Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	44.4	56.3
Level 2 | Diversified Growth Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	44.5	48.0
Level 2 | Liability Driven Investments
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	31.7	38.7
Level 2 | Index Linked Gilts
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	57.0	52.1
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	6.2	6.5	$ 5.7
Actual return on plan assets	0.2	0.3
Purchases, sales and settlements	(0.2)	(0.3)
Currency translation adjustments	(0.3)	0.8
Level 3 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	4.2	4.2	3.6
Actual return on plan assets	0.2	0.2
Purchases, sales and settlements		(0.1)
Currency translation adjustments	(0.2)	0.5
Level 3 | Diversified Investment, Funds
Defined Benefit Plan Disclosure [Line Items]
Fair value measurements	2.0	2.3	$ 2.1
Actual return on plan assets		0.1
Purchases, sales and settlements	(0.2)	(0.2)
Currency translation adjustments	$ (0.1)	$ 0.3