Business Segments and Related Information - Allocation of Net Derivative Gains (Losses) from Economic Hedges of Forecasted Commodity Consumption and Foreign Currency Risk (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 25, 2012	Nov. 27, 2011	Nov. 25, 2012	Nov. 27, 2011
Operating Statistics [Line Items]
Net derivative gains (losses) incurred	$ (12.0)	$ (20.2)	$ 108.2	$ (32.6)
Net derivative gains (losses) allocated to reporting segments	4.1	7.0	(5.9)	28.1
Net derivative gains (losses) recognized in general corporate expenses	(16.1)	(27.2)	114.1	(60.7)
Consumer Foods [Member]
Operating Statistics [Line Items]
Net derivative gains (losses) allocated to reporting segments	6.2	6.7	2.3	24.8
Commercial Foods [Member]
Operating Statistics [Line Items]
Net derivative gains (losses) allocated to reporting segments	$ (2.1)	$ 0.3	$ (8.2)	$ 3.3