STOCKHOLDERS' EQUITY (Reconciliation of Stockholders Equity) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				3 Months Ended
	Aug. 25, 2013	Aug. 26, 2012	Aug. 25, 2013 Common Stock	May 26, 2013 Common Stock	Aug. 25, 2013 Additional Paid-in Capital	Aug. 25, 2013 Retained Earnings	Aug. 25, 2013 Accumulated Other Comprehensive Income (Loss)	Aug. 25, 2013 Treasury Stock	Aug. 25, 2013 Noncontrolling Interests
Schedule Of Stockholders Equity [Line Items]
Opening Balance	$ 5,363.0		$ 2,839.7	$ 2,839.7	$ 1,006.2	$ 5,129.5	$ (196.1)	$ (3,514.9)	$ 98.6
Opening Balance, Shares			567.9	567.9
Stock option and incentive plans	77.1				(1.4)	(0.3)		78.8
Currency translation adjustment	(31.0)						(19.0)		(12.0)
Issuance of treasury shares	0
Repurchase of common shares	(41.7)							(41.7)
Unrealized gain on securities	0.1						0.1
Derivative adjustment, net of reclassification adjustment	45.6	(2.7)					45.6
Activities of noncontrolling interests	0.1				(0.4)				0.5
Pension and postretirement healthcare benefits	(0.2)	0.9					(0.2)
Dividends declared on common stock; $0.25 per share	(105.5)					(105.5)
Net income attributable to ConAgra Foods, Inc.	144.3	250.1				144.3
Ending Balance	$ 5,451.8		$ 2,839.7	$ 2,839.7	$ 1,004.4	$ 5,168.0	$ (169.6)	$ (3,477.8)	$ 87.1
Ending Balance, Shares			567.9	567.9