Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Millions		Total		Total Avient shareholders' equity		Common Shares	Common Shares Held in Treasury	Additional Paid-in Capital	Retained Earnings		Accumulated Other Comprehensive (Loss) Income	Non-controlling Interests
Beginning balance (in shares) at Dec. 31, 2018						122,200
Beginning balance, Treasury shares (in shares) at Dec. 31, 2018							(44,500)
Beginning balance at Dec. 31, 2018		$ 540.6		$ 540.0		$ 1.2	$ (1,018.7)	$ 1,166.9	$ 472.9		$ (82.3)	$ 0.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		38.3		38.2					38.2			0.1
Other comprehensive (loss) income		3.2		3.2							3.2
Cash dividends declared	[1]	(14.8)		(14.8)					(14.8)
Share-based compensation and exercise of awards (in shares)							100
Share-based compensation and exercise of awards		1.6		1.6			$ 1.1	0.5
Ending balance (in shares) at Mar. 31, 2019						122,200
Ending balance, Treasury shares (in shares) at Mar. 31, 2019							(44,400)
Ending balance at Mar. 31, 2019		568.9		568.2		$ 1.2	$ (1,017.6)	1,167.4	496.3		(79.1)	0.7
Beginning balance (in shares) at Dec. 31, 2018						122,200
Beginning balance, Treasury shares (in shares) at Dec. 31, 2018							(44,500)
Beginning balance at Dec. 31, 2018		540.6		540.0		$ 1.2	$ (1,018.7)	1,166.9	472.9		(82.3)	0.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		123.5
Ending balance (in shares) at Sep. 30, 2019						122,200
Ending balance, Treasury shares (in shares) at Sep. 30, 2019							(45,300)
Ending balance at Sep. 30, 2019		592.2		591.4		$ 1.2	$ (1,043.3)	1,171.6	551.5		(89.6)	0.8
Beginning balance (in shares) at Mar. 31, 2019						122,200
Beginning balance, Treasury shares (in shares) at Mar. 31, 2019							(44,400)
Beginning balance at Mar. 31, 2019		568.9		568.2		$ 1.2	$ (1,017.6)	1,167.4	496.3		(79.1)	0.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		42.1		42.1					42.1			0.0
Other comprehensive (loss) income		(0.3)		(0.3)							(0.3)
Cash dividends declared	[1]	(15.2)		(15.2)					(15.2)
Repurchase of common shares (in shares)							(1,000)
Repurchase of common shares		(26.9)		(26.9)			$ (26.9)
Share-based compensation and exercise of awards (in shares)							100
Share-based compensation and exercise of awards		2.5		2.5			$ 0.7	1.8
Ending balance (in shares) at Jun. 30, 2019						122,200
Ending balance, Treasury shares (in shares) at Jun. 30, 2019							(45,300)
Ending balance at Jun. 30, 2019		571.1		570.4		$ 1.2	$ (1,043.8)	1,169.2	523.2		(79.4)	0.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		43.1		43.0					43.0			0.1
Other comprehensive (loss) income		(10.2)		(10.2)							(10.2)
Cash dividends declared		(14.7)		(14.7)					(14.7)
Share-based compensation and exercise of awards (in shares)							0
Share-based compensation and exercise of awards		2.9		2.9			$ 0.5	2.4
Ending balance (in shares) at Sep. 30, 2019						122,200
Ending balance, Treasury shares (in shares) at Sep. 30, 2019							(45,300)
Ending balance at Sep. 30, 2019		592.2		591.4		$ 1.2	$ (1,043.3)	1,171.6	551.5		(89.6)	0.8
Beginning balance (in shares) at Dec. 31, 2019						122,200
Beginning balance, Treasury shares (in shares) at Dec. 31, 2019							(45,300)
Beginning balance at Dec. 31, 2019		1,052.7		1,051.9		$ 1.2	$ (1,043.1)	1,175.2	1,001.2		(82.6)	0.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		32.8		32.8					32.8			0.0
Other comprehensive (loss) income		(10.7)		(10.7)							(10.7)
Noncontrolling interest activity		(0.8)										(0.8)
Cash dividends declared		(18.7)	[2]	(18.7)	[2]				(18.7)	[1]
Repurchase of common shares (in shares)							(1,000)
Repurchase of common shares		(13.6)		(13.6)			$ (13.6)
Common shares equity offering (in shares)							15,300
Common shares equity offering		496.1		496.1		$ 0.2	$ 161.3	334.6
Share-based compensation and exercise of awards (in shares)							200
Share-based compensation and exercise of awards		1.1		1.1			$ 1.6	(0.5)
Other		(0.3)		(0.3)					(0.3)
Ending balance (in shares) at Mar. 31, 2020						122,200
Ending balance, Treasury shares (in shares) at Mar. 31, 2020							(30,800)
Ending balance at Mar. 31, 2020		1,538.6		1,538.6		$ 1.4	$ (893.8)	1,509.3	1,015.0		(93.3)	0.0
Beginning balance (in shares) at Dec. 31, 2019						122,200
Beginning balance, Treasury shares (in shares) at Dec. 31, 2019							(45,300)
Beginning balance at Dec. 31, 2019		1,052.7		1,051.9		$ 1.2	$ (1,043.1)	1,175.2	1,001.2		(82.6)	0.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		58.6
Ending balance (in shares) at Sep. 30, 2020						122,200
Ending balance, Treasury shares (in shares) at Sep. 30, 2020							(30,800)
Ending balance at Sep. 30, 2020		1,611.1		1,597.0		$ 1.4	$ (892.9)	1,514.4	1,002.5		(28.4)	14.1
Beginning balance (in shares) at Mar. 31, 2020						122,200
Beginning balance, Treasury shares (in shares) at Mar. 31, 2020							(30,800)
Beginning balance at Mar. 31, 2020		1,538.6		1,538.6		$ 1.4	$ (893.8)	1,509.3	1,015.0		(93.3)	0.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		23.2		22.8					22.8			0.4
Other comprehensive (loss) income		4.8		4.8							4.8
Cash dividends declared	[2]	(18.5)		(18.5)					(18.5)
Share-based compensation and exercise of awards (in shares)							0
Share-based compensation and exercise of awards		3.6		3.6			$ 0.4	3.2
Ending balance (in shares) at Jun. 30, 2020						122,200
Ending balance, Treasury shares (in shares) at Jun. 30, 2020							(30,800)
Ending balance at Jun. 30, 2020		1,551.7		1,551.3		$ 1.4	$ (893.4)	1,512.5	1,019.3		(88.5)	0.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		2.6		1.7					1.7			0.9
Other comprehensive (loss) income		60.1		60.1							60.1
Cash dividends declared		(18.5)		(18.5)					(18.5)
Share-based compensation and exercise of awards		2.4		2.4			$ 0.5	1.9
Acquisitions/other		12.8										12.8
Ending balance (in shares) at Sep. 30, 2020						122,200
Ending balance, Treasury shares (in shares) at Sep. 30, 2020							(30,800)
Ending balance at Sep. 30, 2020		$ 1,611.1		$ 1,597.0		$ 1.4	$ (892.9)	$ 1,514.4	$ 1,002.5		$ (28.4)	$ 14.1

[1] (1) Dividends declared per share were $0.1950 and $0.5850 for the three and nine months ended September 30, 2019, respectively.

[2] (1) Dividends declared per share were $0.2025 and $0.6075 for the three and nine months ended September 30, 2020, respectively.