CONTINGENCIES (Details) $ in Millions		3 Months Ended					12 Months Ended
	Jan. 27, 2014 USD ($) defendant	Nov. 23, 2014 USD ($)	Aug. 24, 2014 USD ($)	May. 25, 2014 USD ($)	Nov. 24, 2013 USD ($)	Feb. 24, 2013 USD ($)	May. 31, 2015 USD ($) site	May. 25, 2014 USD ($)	May. 26, 2013 USD ($)	May. 27, 2012 USD ($)
Guarantor Obligations [Line Items]
Possible loss contingency amount							$ 11.2
Reserves for Beatrice environmental matters				$ 63.0			55.0	$ 63.0
Loan purchase under agreement										$ 40.8
Asset impairment charges							1,615.3	720.0	$ 20.2
Face value of federal income tax credits							$ 26.7
Dispute coverage charge with insurance carrier									$ 7.5	17.5
Reduction to accrual		$ 1.2	$ 5.8	6.7
Lamb Weston Meijer
Guarantor Obligations [Line Items]
Ownership percentage							50.00%
Total liabilities				144.7			$ 129.1	144.7
Partners' equity				247.0			$ 255.9	$ 247.0
Commercial Foods
Guarantor Obligations [Line Items]
Asset impairment charges					$ 8.9	$ 10.2
Gain on sale of land				$ 5.1
Beatrice
Guarantor Obligations [Line Items]
Number of sites under environmental matters for which acquired company has a liability | site							37
Number of sites under environmental matters for which acquired company is making payments | site							33
Reserves for Beatrice environmental matters							$ 53.7
Maximum period expected for disbursements on environmental matters							18 years
Beatrice | CALIFORNIA
Guarantor Obligations [Line Items]
Other defendants | defendant	2
Possible loss contingency amount	$ 1,150.0
Potato Supply Agreement Guarantee
Guarantor Obligations [Line Items]
Amount of supplier loans effectively guaranteed							$ 39.3
Onion Supply Agreement Guarantee
Guarantor Obligations [Line Items]
Guarantee obligation under purchase agreement										$ 25.0
Leases and Other Commercial Obligations Guarantee
Guarantor Obligations [Line Items]
Guarantee obligation under purchase agreement							$ 2.7