Basis of Presentation and Responsibility for Interim Financial Statements - Adoption of New Accounting Standards (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Lease, Liability, Current	$ 19.9		$ 0.0
Operating Lease, Liability, Noncurrent	57.7		0.0
Net periodic benefit cost	1.7	$ 1.8
Operating Lease, Right-of-Use Asset	$ 74.7		$ 0.0