Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended	12 Months Ended			3 Months Ended			6 Months Ended			6 Months Ended
	Nov. 25, 2012	May 27, 2012	Nov. 25, 2012 Hogs	May 27, 2012	May 31, 2009	Aug. 26, 2012	Aug. 26, 2012 Litigation Matter [Member]	Aug. 26, 2012 Compensatory Damages [Member]	Aug. 26, 2012 Punitive Damages [Member]	Nov. 25, 2012 Beatrice [Member] site	Nov. 25, 2012 Potato Supply Agreement Guarantee [Member]	Nov. 25, 2012 Onion Supply Agreement Guarantee [Member]	Nov. 25, 2012 Leases and Other Commercial Obligations Guarantee [Member]
Guarantor Obligations [Line Items]
Number of sites under environmental matters for which acquired company has a liability										36
Number of sites under environmental matters for which acquired company is making payments										32
Reserves for Beatrice environmental matters										$ 73.0
Maximum period expected for disbursements on environmental matters										18 years
Maximum period of guarantee													3 Years
Guarantee obligation under purchase agreement												25.0	9.5
Minimum quantity of hogs to be purchased under hog purchase agreement through 2014			1,200,000
Amount of supplier loans effectively guaranteed											30.3
Loan purchase under agreement		40.8		40.8
Face value of federal income tax credits	21.2		21.2
Dispute coverage charge with insurance carrier				17.5	24.8		7.5
Favorable claim related to defense cost	1.1	11.8
Favorable claim for disputed coverage		25.0
Pre-Judgment interest	4.7
Unfavorable Verdict								77.5	100.0
Damages accrued in prior period						$ 3