Acquisitions - Schedule of Acquisitions (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill	$ 883.2	$ 883.2
Packaging
Business Acquisition [Line Items]
Goodwill	$ 828.0	828.0
Sacramento Container Corporation
Business Acquisition [Line Items]
Other intangible assets		72.6
Property, plant and equipment		26.7
Other net assets		23.4
Net assets acquired		273.8
Sacramento Container Corporation | Packaging
Business Acquisition [Line Items]
Goodwill		$ 151.1