Acquisitions and Dispositions - Schedule of Acquisitions (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
	Oct. 02, 2017	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 883.2		$ 883.2	$ 737.9	$ 544.0
Packaging
Business Acquisition [Line Items]
Goodwill		828.0		828.0	682.7	$ 488.8
Sacramento Container Corporation
Business Acquisition [Line Items]
Other intangible assets	$ 72.6	72.6		72.6
Property, plant and equipment	26.7	26.7		26.7
Other net assets	14.6	23.4		23.4
Net assets acquired	265.0	273.8		273.8
Other net assets, Adjustments	8.8	8.8
Net assets acquired, Adjustments		8.8
Sacramento Container Corporation | Packaging
Business Acquisition [Line Items]
Goodwill	$ 151.1	151.1		151.1
Columbus Container Inc
Business Acquisition [Line Items]
Other intangible assets		32.3		32.3	26.3
Property, plant and equipment		28.2		28.2	27.2
Other net assets		9.5		9.5	9.6
Net assets acquired		101.9		101.9	99.7
Goodwill, Adjustments			$ 2.2	(4.7)
Other intangible assets, Adjustments				6.0
Property, plant and equipment, Adjustments				1.0
Other net assets, Adjustments				(0.1)
Net assets acquired, Adjustments				2.2
Columbus Container Inc | Packaging
Business Acquisition [Line Items]
Goodwill		31.9		31.9	36.6
TimBar Corporation
Business Acquisition [Line Items]
Other intangible assets		94.4		94.4	94.4
Property, plant and equipment		95.3		95.3	95.3
Other net assets		38.6		38.6	38.6
Net assets acquired		384.5		384.5	385.6
Goodwill, Adjustments				(1.1)
Net assets acquired, Adjustments				(1.1)
TimBar Corporation | Packaging
Business Acquisition [Line Items]
Goodwill		$ 156.2		$ 156.2	$ 157.3