Condensed Consolidated Statements of Equity (Unaudited) - USD ($) $ in Millions		Total	Common Stock	Capital in Excess of Par Value	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive (Loss) Income	Noncontrolling Interests
Beginning Balance (in shares) at Dec. 31, 2018			299,807,779
Beginning balance at Dec. 31, 2018		$ 2,018.5	$ 3.0	$ 1,944.4	$ 10.0	$ (377.9)	$ 439.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)		73.5			57.9		15.6
Other Comprehensive (Loss) Income, Net of Tax:
Derivative Instruments		(0.5)				(0.4)	(0.1)
Pension and Postretirement Benefit Plans		1.4				1.2	0.2
Currency Translation Adjustment		4.8				3.9	0.9
Repurchase of Common Stock (in shares)	[1]		(5,033,426)
Repurchase of Common Stock	[1]	(59.5)	$ (0.1)	(27.2)	(32.2)
Dividends Declared		(22.1)			(22.1)
Reclassification of Redeemable Noncontrolling Interest for Share Repurchases		(6.7)					(6.7)
Distribution of Membership Interest		(5.0)					(5.0)
Recognition of Stock-Based Compensation, Net		0.9		0.9
Issuance of Shares for Stock-Based Awards (in shares)			530,196
Ending Balance (in shares) at Mar. 31, 2019			295,304,549
Ending balance at Mar. 31, 2019		2,005.3	$ 2.9	1,918.1	13.6	(373.2)	443.9
Beginning Balance (in shares) at Dec. 31, 2018			299,807,779
Beginning balance at Dec. 31, 2018		2,018.5	$ 3.0	1,944.4	10.0	(377.9)	439.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income Attributable to Graphic Packaging Holding Company		173.8
Other Comprehensive (Loss) Income, Net of Tax:
Repurchase of Common Stock (in shares)			(3,729,361)
Repurchase of Common Stock		(50.1)		(20.2)	(29.9)
Ending Balance (in shares) at Sep. 30, 2019			290,244,799
Ending balance at Sep. 30, 2019		2,034.6	$ 2.9	1,901.4	45.1	(392.8)	478.0
Beginning Balance (in shares) at Mar. 31, 2019			295,304,549
Beginning balance at Mar. 31, 2019		2,005.3	$ 2.9	1,918.1	13.6	(373.2)	443.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)		81.0			63.8		17.2
Other Comprehensive (Loss) Income, Net of Tax:
Derivative Instruments		(5.7)				(4.4)	(1.3)
Pension and Postretirement Benefit Plans		1.3				0.9	0.4
Currency Translation Adjustment		(3.2)				(2.6)	(0.6)
Repurchase of Common Stock (in shares)			(1,428,470)
Repurchase of Common Stock		(18.3)		(7.7)	(10.6)
Dividends Declared		(22.1)			(22.1)
Reclassification of Redeemable Noncontrolling Interest for Share Repurchases		19.1					19.1
Distribution of Membership Interest		(6.4)					(6.4)
Recognition of Stock-Based Compensation, Net		5.9		5.9
Issuance of Shares for Stock-Based Awards (in shares)			94,327
Issuance of Shares for Stock-Based Awards		0.0
Ending Balance (in shares) at Jun. 30, 2019			293,970,406
Ending balance at Jun. 30, 2019		2,056.9	$ 2.9	1,916.3	44.7	(379.3)	472.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)		65.9					13.8
Net Income Attributable to Graphic Packaging Holding Company		52.1
Other Comprehensive (Loss) Income, Net of Tax:
Pension and Postretirement Benefit Plans		1.4				1.1	0.3
Currency Translation Adjustment		(17.7)				(14.6)	(3.1)
Dividends Declared		(21.8)			(21.8)
Distribution of Membership Interest		(5.3)					(5.3)
Recognition of Stock-Based Compensation, Net		5.3		5.3
Issuance of Shares for Stock-Based Awards (in shares)			3,754
Issuance of Shares for Stock-Based Awards		0.0
Ending Balance (in shares) at Sep. 30, 2019			290,244,799
Ending balance at Sep. 30, 2019		$ 2,034.6	$ 2.9	1,901.4	45.1	(392.8)	478.0
Beginning Balance (in shares) at Dec. 31, 2019		290,246,907	290,246,907
Beginning balance at Dec. 31, 2019		$ 2,058.0	$ 2.9	1,876.7	56.4	(365.8)	487.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)		(14.5)			(12.7)		(1.8)
Other Comprehensive (Loss) Income, Net of Tax:
Derivative Instruments		(1.3)				(1.0)	(0.3)
Pension and Postretirement Benefit Plans		145.7				113.3	32.4
Currency Translation Adjustment		(56.0)				(46.0)	(10.0)
Repurchase of Common Stock (in shares)	[2]		(9,667,034)
Repurchase of Common Stock	[2]	(124.4)	$ (0.1)	(52.6)	(71.7)
Dividends Declared		(21.1)			(21.1)
Redeemable Noncontrolling Interest Redemption Value Adjustment		18.1		18.1
Tax Effect of IP Redemption		6.8		6.8
Distribution of Membership Interest		(4.6)					(4.6)
Recognition of Stock-Based Compensation, Net		3.6		3.6
Issuance of Shares for Stock-Based Awards (in shares)			788,561
Issuance of Shares for Stock-Based Awards		0.0
Ending Balance (in shares) at Mar. 31, 2020			281,368,434
Ending balance at Mar. 31, 2020		$ 2,010.3	$ 2.8	1,852.6	(49.1)	(299.5)	503.5
Beginning Balance (in shares) at Dec. 31, 2019		290,246,907	290,246,907
Beginning balance at Dec. 31, 2019		$ 2,058.0	$ 2.9	1,876.7	56.4	(365.8)	487.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income Attributable to Graphic Packaging Holding Company		103.1
Other Comprehensive (Loss) Income, Net of Tax:
Redeemable Noncontrolling Interest Redemption Value Adjustment		12.2
Reclassification of Redeemable Noncontrolling Interest for Share Repurchases		$ (296.1)
Ending Balance (in shares) at Sep. 30, 2020		272,545,029	272,236,844
Ending balance at Sep. 30, 2020		$ 1,833.9	$ 2.7	1,732.4	(52.0)	(255.5)	406.3
Beginning Balance (in shares) at Mar. 31, 2020			281,368,434
Beginning balance at Mar. 31, 2020		2,010.3	$ 2.8	1,852.6	(49.1)	(299.5)	503.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)		66.6			52.1		14.5
Other Comprehensive (Loss) Income, Net of Tax:
Derivative Instruments		3.0				2.3	0.7
Pension and Postretirement Benefit Plans		0.3				0.3
Currency Translation Adjustment		13.9				11.3	2.6
Repurchase of Common Stock (in shares)			(2,622,283)
Repurchase of Common Stock		(33.1)		(14.3)	(18.8)
Dividends Declared		(21.3)			(21.3)
Redeemable Noncontrolling Interest Redemption Value Adjustment		(5.4)		(5.4)
Distribution of Membership Interest		(5.6)					(5.6)
Recognition of Stock-Based Compensation, Net		7.9		7.9
Issuance of Shares for Stock-Based Awards (in shares)			93,381
Issuance of Shares for Stock-Based Awards		0.0
Ending Balance (in shares) at Jun. 30, 2020			278,839,532
Ending balance at Jun. 30, 2020		2,036.6	$ 2.8	1,840.8	(37.1)	(285.6)	515.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)		77.3			63.7		13.6
Net Income Attributable to Graphic Packaging Holding Company		63.7
Other Comprehensive (Loss) Income, Net of Tax:
Derivative Instruments		6.6					1.1
Pension and Postretirement Benefit Plans		0.9				0.8	0.1
Currency Translation Adjustment		28.1				23.8	4.3
Repurchase of Common Stock (in shares)			(6,607,221)
Repurchase of Common Stock		(94.1)	$ (0.1)	(36.0)	(58.0)
Dividends Declared		(20.6)			(20.6)
Redeemable Noncontrolling Interest Redemption Value Adjustment		(0.5)		(0.5)
Reclassification of Redeemable Noncontrolling Interest for Share Repurchases		(210.9)		(87.4)			(123.5)
Tax Effect of IP Redemption		9.2		9.2
Distribution of Membership Interest		(5.0)					(5.0)
Recognition of Stock-Based Compensation, Net		6.3		6.3
Issuance of Shares for Stock-Based Awards (in shares)			4,533
Issuance of Shares for Stock-Based Awards		$ 0.0
Ending Balance (in shares) at Sep. 30, 2020		272,545,029	272,236,844
Ending balance at Sep. 30, 2020		$ 1,833.9	$ 2.7	$ 1,732.4	$ (52.0)	(255.5)	$ 406.3
Other Comprehensive (Loss) Income, Net of Tax:
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Parent						$ 5.5

[1] Includes 33,263 shares repurchased but not yet settled as of March 31, 2019.

[2] Includes 410,400 shares repurchased but not yet settled as of March 31, 2020. ^(b) Includes 14,436 shares repurchased but not yet settled as of June 30, 2020. ^(c) Includes 308,185 shares repurchased but not yet settled as of September 30, 2020.