Condensed Consolidated Statements of Equity and Redeemable Noncontrolling Interest (Parenthetical)	3 Months Ended
Mar. 31, 2020 shares
Statement of Stockholders' Equity [Abstract]
Shares repurchased but not yet settled (in shares)	410,400

Stock Repurchased During Period, Not Settled, Shares

No definition available.

Name:	gpk_StockRepurchasedDuringPeriodNotSettledShares
Namespace Prefix:	gpk_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration