Business Combinations Narrative (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended		0 Months Ended				0 Months Ended	9 Months Ended
	Mar. 31, 2014	Sep. 30, 2014	Sep. 30, 2013	Mar. 13, 2013 Spartech [Member]	Sep. 30, 2014 Senior Notes [Member] 5.250% Senior Notes Due 2023 [Member]	Dec. 31, 2013 Senior Notes [Member] 5.250% Senior Notes Due 2023 [Member]	Feb. 28, 2013 Senior Notes [Member] 5.250% Senior Notes Due 2023 [Member]	Mar. 13, 2013 Senior Notes [Member] Spartech's 7.08% Senior Notes due 2016 [Member] Spartech [Member]	Sep. 30, 2013 Selling, General and Administrative Expenses [Member]
Business Acquisition [Line Items]
Goodwill, Purchase Accounting Adjustments	$ 9.4
Payments to Acquire Businesses, Gross				83.4
Business acquisition, aggregate consideration transferred for each common share				$ 2.67
Exchange ratio				0.3167
PolyOne shares issued				10.0
Stated interest rate					5.25%	5.25%	5.25%	7.08%
Fair value of Spartech equity awards, net of deferred tax benefits				2.4
Fair Value of Spartech Equity Awards, before deferred tax benefits				3.9
Deferred tax benefit				1.5
Vested in period, total fair value				2.7
Line of Credit Facility, Decrease, Repayments		20.9	117.5	77.2
Early repayment of senior debt				102.3				102.3
Business acquisition, principal repayment of senior notes.								88.9
Make-whole provision								10.3
Interest payable								3.1
Acquisition related costs									$ 7.2