Condensed Consolidated Statements of Equity and Redeemable Noncontrolling Interest (Parenthetical) - shares	3 Months Ended
Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020
Statement of Stockholders' Equity [Abstract]
Shares repurchased but not yet settled (in shares)	308,185	14,436	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