Equity - Schedule of Changes in Equity (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Changes in Equity [Rollforward]
Balance at beginning of period	$ 705.2	$ 777.2
Net income	39.0	30.2
Other comprehensive income
Translation adjustments	(0.2)	(17.9)
Total comprehensive income	38.8	12.3
Cash dividend declared	(9.8)	(8.9)
Repurchase of common shares	(39.6)	(19.6)
Share-based incentive plan activity	(1.1)	(1.9)
Balance at end of period	693.5	759.1
PolyOne Shareholders' Equity
Changes in Equity [Rollforward]
Balance at beginning of period	704.2	776.3
Net income	39.1	30.2
Other comprehensive income
Translation adjustments	(0.2)	(17.9)
Total comprehensive income	38.9	12.3
Cash dividend declared	(9.8)	(8.9)
Repurchase of common shares	(39.6)	(19.6)
Share-based incentive plan activity	(1.1)	(1.9)
Balance at end of period	692.6	758.2
Noncontrolling Interests
Changes in Equity [Rollforward]
Balance at beginning of period	1.0	0.9
Net income	(0.1)	0.0
Other comprehensive income
Translation adjustments	0.0	0.0
Total comprehensive income	(0.1)	0.0
Cash dividend declared	0.0	0.0
Repurchase of common shares	0.0	0.0
Share-based incentive plan activity	0.0	0.0
Balance at end of period	$ 0.9	$ 0.9