Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Sales	$ 901.6	$ 796.7
Cost of sales	703.1	614.5
Gross margin	198.5	182.2
Selling and administrative expense	119.7	100.2
Operating income	78.8	82.0
Interest expense, net	(15.5)	(14.6)
Debt extinguishment costs	0.0	(0.3)
Other income, net	1.1	0.9
Income from continuing operations before income taxes	64.4	68.0
Income tax expense	(16.7)	(19.7)
Net income from continuing operations	47.7	48.3
Loss from discontinued operations, net of income taxes	(0.8)	(1.4)
Net income attributable to PolyOne common shareholders	$ 46.9	$ 46.9
Earnings (loss) per common share attributable to PolyOne common shareholders - Basic:
Earnings (loss) from continuing operations per common share attributable to PolyOne common shareholders - Basic (in USD per share)	$ 0.59	$ 0.58
Earnings (loss) from discontinued operations per common share attributable to PolyOne common shareholders - Basic (in USD per share)	(0.01)	(0.01)
Earnings (loss) per common share attributable to PolyOne common shareholders - Basic (in USD per share)	0.58	0.57
Earnings (loss) per common share attributable to PolyOne common shareholders - Diluted:
Earnings (loss) from continuing operations per common share attributable to PolyOne common shareholders - Diluted (in USD per share)	0.59	0.58
Earnings (loss) from discontinued operations per common share attributable to PolyOne common shareholders - Diluted (in USD per share)	(0.01)	(0.01)
Earnings (loss) per common share attributable to PolyOne common shareholders - Diluted (in USD per share)	$ 0.58	$ 0.57
Weighted-average shares used to compute earnings per common share:
Basic (in shares)	80.4	82.1
Plus dilutive impact of share-based compensation (in shares)	0.9	0.6
Diluted (in shares)	81.3	82.7
Anti-dilutive shares not included in diluted common shares outstanding (in shares)	0.1	0.3
Cash dividends declared per share of common stock (in USD per share)	$ 0.175	$ 0.135