Accumulated Other Comprehensive (Loss) - Schedule of Changes in AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 2,056.9	$ 2,168.4	$ 2,018.5	$ 1,291.9
Other Comprehensive (Loss) Income before Reclassifications			(23.0)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)			3.8
Other Comprehensive Income (Loss), Net of Tax	(17.1)	4.2	(19.2)	(3.3)
Ending balance	2,034.6	2,261.7	2,034.6	2,261.7
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			(3.8)
Other Comprehensive Income (Loss), Net of Tax	(17.1)	4.2	(19.2)	(3.3)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(379.3)	(344.9)	(377.9)	(338.8)
Ending balance	(392.8)	$ (341.7)	(392.8)	$ (341.7)
Derivatives Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(11.3)
Ending balance	(16.1)		(16.1)
Pension and Postretirement Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(246.1)
Ending balance	(242.9)		(242.9)
Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(120.5)
Ending balance	(133.8)		(133.8)
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other Comprehensive (Loss) Income before Reclassifications			(5.9)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)			(0.7)
Other Comprehensive Income (Loss), Net of Tax			(6.6)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			0.7
Other Comprehensive Income (Loss), Net of Tax			(6.6)
Pension and Postretirement Benefit Plans, Portion Attributable to NCI and Redeemable NCI
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax			(1.2)
Other Comprehensive Income (Loss), Net of Tax			(1.2)
Currency Translation Adjustment, Portion Attributable to NCI and Redeemable NCI
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax			3.7
Other Comprehensive Income (Loss), Net of Tax			3.7
Pension and Postretirement Benefit Plan, Including Portion Attributable to NCI and Redeemable NCI
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other Comprehensive (Loss) Income before Reclassifications			(0.1)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)			4.5
Other Comprehensive Income (Loss), Net of Tax			4.4
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			(4.5)
Other Comprehensive Income (Loss), Net of Tax			4.4
Accumulated Gain (Loss), Net, Cash Flow Hedge, Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax			1.8
Other Comprehensive Income (Loss), Net of Tax			1.8
Graphic Packaging Holding Company, Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(1.9)
Ending balance	$ (10.1)		(10.1)
AOCI Attributable to Noncontrolling Interest And Redeemable Noncontrolling Interest
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax			4.3
Other Comprehensive Income (Loss), Net of Tax			4.3
Currency Translation Adjustment, Including Portion Attributable to NCI and Redeemable NCI
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other Comprehensive (Loss) Income before Reclassifications			(17.0)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)			0.0
Other Comprehensive Income (Loss), Net of Tax			(17.0)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			0.0
Other Comprehensive Income (Loss), Net of Tax			$ (17.0)