Note 15 - Contingencies (Details Textual) $ in Millions			12 Months Ended			35 Months Ended
	May 24, 2022 USD ($)	Feb. 18, 2022 USD ($)	May 29, 2022 USD ($)	May 30, 2021 USD ($)	May 31, 2020 USD ($)	May 29, 2022 USD ($)	Sep. 04, 2018 USD ($)	Jan. 27, 2014 USD ($)
Threshold Amount For Environmental Matters			$ 1.0
Lamb Weston Holdings Inc [Member]
Lessee, Operating Lease, Renewal Term (Year)			5 years			5 years
Beatrice [Member]
Accrual for Environmental Loss Contingencies, Ending Balance			$ 39.9			$ 39.9
Accrual for Environmental Loss Contingencies, Decrease from Settlement Agreement With Third Party	$ 6.5
Beatrice [Member] | Other Accrued Liabilities [Member]
Accrual for Environmental Loss Contingencies, Ending Balance			2.0			2.0
Beatrice [Member] | Other Noncurrent Liabilities [Member]
Accrual for Environmental Loss Contingencies, Ending Balance			37.9			37.9
MPCA [Member]
Accrued Environmental Loss Contingencies, Proposed Penalty Amount				$ 4.3	$ 1.8
Performance And Payment Guarantee [Member]
Guarantor Obligations, Maximum Exposure, Undiscounted			75.0			75.0
Property Lease Guarantee [Member]
Guarantor Obligations, Maximum Exposure, Undiscounted			$ 11.3			11.3
Lease Remaining Lease Terms (Year)			5 years
ILLINOIS
Loss Contingency Number Of Suits			1
Litigation Settlement, Expense		$ 9.4
CANADA | Beatrice [Member]
Loss Contingency, Estimate of Possible Loss							$ 409.0	$ 1,150.0
Litigation Settlement, Amount Awarded to Other Party				$ 101.7
Loss Contingency Settlement Agreement Terms Number Of Installments				7
Loss Contingency Accrual, Payments						49.0
CANADA | Beatrice [Member] | Maximum [Member]
Litigation Settlement Amount Of Guarantee				$ 15.0
CANADA | Beatrice [Member] | Maximum [Member] | Other Current Liabilities [Member]
Loss Contingency Accrual, Ending Balance			$ 40.5			40.5
CANADA | Beatrice [Member] | Minimum [Member] | Other Current Liabilities [Member]
Loss Contingency Accrual, Ending Balance			$ 11.7			$ 11.7