RESTRUCTURING (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	May 26, 2013 Ralcorp Restructuring	May 26, 2013 Network Optimization Plan	May 26, 2013 Acquisition-Related Restructuring	May 26, 2013 Administrative Efficiency Restructuring Plan	May 27, 2012 2010 Restructuring Plan	May 29, 2011 2010 Restructuring Plan	May 30, 2010 2010 Restructuring Plan	May 26, 2013 Ralcorp Pre-Acquisition Restructure Transactions	May 26, 2013 Ralcorp Restructuring
Restructuring Cost and Reserve [Line Items]
Restructured and related cost incurred to date		$ 76.7	$ 14.0	$ 18.7
Restructuring and related cost expected outflows			14.3						28.4
Restructuring and related cost, expected cost			14.3					3.2
Expenses that have resulted or will result in cash outflows		17.9	10.2	16.8
Non-cash expenses		58.8	4.1	1.9
Costs incurred and charged to expense	28.4	3.7	7.0	1.5	2.6	25.7	67.3
Restructuring and related cost, incurred cost	$ 28.4	$ 4.3	$ 9.5	$ 2.0				$ 1.3