Segment Information - Schedule of Segment Information (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Net sales	$ 1,594.6	$ 1,501.6
Net Sales	1,599.1	1,505.9
Income (Loss) from Operations	160.0	134.0
Depreciation and Amortization	113.6	117.1
Corporate/Other/Eliminations
Segment Reporting Information [Line Items]
Net Sales	30.4	33.8
Income (Loss) from Operations	(23.9)	(6.8)
Depreciation and Amortization	5.4	5.4
Paperboard Mills \| Operating Segments
Segment Reporting Information [Line Items]
Net sales	268.5	275.5
Income (Loss) from Operations	(22.9)	(4.0)
Depreciation and Amortization	59.0	56.2
Americas Paperboard Packaging \| Operating Segments
Segment Reporting Information [Line Items]
Net sales	1,123.4	1,022.8
Income (Loss) from Operations	194.8	125.6
Depreciation and Amortization	39.4	43.7
Europe Paperboard Packaging \| Operating Segments
Segment Reporting Information [Line Items]
Net sales	176.8	173.8
Income (Loss) from Operations	12.0	19.2
Depreciation and Amortization	$ 9.8	$ 11.8

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