Document and Entity Information - shares	9 Months Ended
	Jun. 30, 2022	Jul. 22, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Trading Symbol	WRK
Entity Registrant Name	WestRock Company
Entity Central Index Key	0001732845
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		254,298,051
Entity Current Reporting Status	Yes
Title of 12(b) Security	Common Stock, par value $0.01 per share
Entity File Number	001-38736
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	37-1880617
Entity Interactive Data Current	Yes
Security Exchange Name	NYSE
Entity Address, Address Line One	1000 Abernathy Road NE
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30328
City Area Code	770
Local Phone Number	448-2193
Document Quarterly Report	true
Document Transition Report	false