Equity (Changes In Equity) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Oct. 23, 2012
Statement, Equity Component [Line Items]
Business Aquisition, Aggregate consideration transferred to acquiree common shareholders.					$ 2.67
Balance at the beginning			$ 588.3	$ 516.0
Net income	24.0	21.6	68.8	160.3
Translation adjustment	4.2	(14.3)	(1.2)	(1.9)
Amortization of prior service credits, net of tax	(2.7)	(2.8)	(8.2)	(8.2)
Total comprehensive income	25.5	4.5	59.4	150.2
Cash dividend declared			(13.3)	11.1
Repurchase of common shares			(15.9)	(52.6)
Stock incentive plan activity			10.8	6.0
Proceeds received from non-controlling interests			2.4
Balance at the ending	631.7	608.5	631.7	608.5
Amortization of prior service credits, tax			4.9	4.9
PolyOne shareholders' equity [Member]
Statement, Equity Component [Line Items]
Balance at the beginning			588.3	516.0
Net income			68.8
Translation adjustment			(1.2)	(1.9)
Amortization of prior service credits, net of tax			(8.2)	(8.2)
Total comprehensive income			59.4	150.2
Cash dividend declared			13.3	11.1
Repurchase of common shares			(15.9)	(52.6)
Stock incentive plan activity			10.8	6.0
Proceeds received from non-controlling interests			0
Balance at the ending	629.3	608.5	629.3	608.5
Noncontrolling interests [Member]
Statement, Equity Component [Line Items]
Balance at the beginning			0	0
Net income			0	0
Translation adjustment			0	0
Amortization of prior service credits, net of tax			0	0
Total comprehensive income			0	0
Cash dividend declared			0	0
Repurchase of common shares			0	0
Stock incentive plan activity			0	0
Proceeds received from non-controlling interests			2.4
Balance at the ending	$ 2.4	$ 0	$ 2.4	$ 0