QUARTERLY FINANCIAL DATA (unaudited) - Multiemployer Pension Plan (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Feb. 23, 2020	May 31, 2020
QUARTERLY FINANCIAL DATA (unaudited)
Loss related to the withdrawal from a multiemployer pension plan by Lamb Weston RDO	$ (2.6)	$ (2.6)

The amount of gain (loss) related to the withdrawal from a multiemployer pension plan.

No definition available.

Name:	lw_GainLossRelatedToWithdrawalFromMultiemployerPensionPlan
Namespace Prefix:	lw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration