Document and Entity Information - USD ($) $ / shares in Units, $ in Billions	12 Months Ended
	May 31, 2020	Jul. 20, 2020	Nov. 22, 2019
Cover [Abstract]
Entity Central Index Key	0001679273
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	May 31, 2020
Entity File Number	1-37830
Entity Registrant Name	LAMB WESTON HOLDINGS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	61-1797411
Entity Address, Address Line One	599 S. Rivershore Lane
Entity Address, City or Town	Eagle
Entity Address, State or Province	ID
Entity Address, Postal Zip Code	83616
City Area Code	208
Local Phone Number	938-1047
Title of 12(b) Security	Common Stock, $1.00 par value
Trading Symbol	LW
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 12.1
Entity Common Stock, Shares Outstanding		146,059,508
Entity Listing, Par Value Per Share	$ 1.00
Current Fiscal Year End Date	--05-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false