BUSINESS SEGMENTS AND RELATED INFORMATION (Net Derivative Gains (Losses)) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	May 26, 2013	May 27, 2012	May 29, 2011
Allocation of net derivative gains (losses) from economic hedges of forecasted commodity consumption and the foreign currency risk
Net derivative gains (losses) incurred	$ 74.8	$ (66.8)	$ 35.1
Net derivative gains allocated to Reporting Segments	25.0	24.4	0.6
Net derivative gains (losses) recognized in general corporate expenses	49.8	(91.2)	34.5
Net derivative gains (losses) included in segment operating profit	25.0	24.4	0.6
Consumer Foods
Allocation of net derivative gains (losses) from economic hedges of forecasted commodity consumption and the foreign currency risk
Net derivative gains allocated to Reporting Segments	30.9	24.9	3.6
Commercial Foods
Allocation of net derivative gains (losses) from economic hedges of forecasted commodity consumption and the foreign currency risk
Net derivative gains (losses) included in segment operating profit	(5.3)	(0.5)	(3.0)
Ralcorp Food Group
Allocation of net derivative gains (losses) from economic hedges of forecasted commodity consumption and the foreign currency risk
Net derivative gains (losses) included in segment operating profit	(0.3)	0	0
Ralcorp Frozen Bakery Products
Allocation of net derivative gains (losses) from economic hedges of forecasted commodity consumption and the foreign currency risk
Net derivative gains (losses) included in segment operating profit	$ (0.3)	$ 0	$ 0