STOCKHOLDERS' EQUITY (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				3 Months Ended
	Aug. 24, 2014	Aug. 25, 2013	Aug. 24, 2014 Common Stock	May 25, 2014 Common Stock	Aug. 24, 2014 Additional Paid-in Capital	Aug. 24, 2014 Retained Earnings	Aug. 24, 2014 Accumulated Other Comprehensive Income (Loss)	Aug. 24, 2014 Treasury Stock	Aug. 24, 2014 Noncontrolling Interests
Schedule Of Stockholders Equity [Line Items]
Balance at	$ 5,355.2		$ 2,839.7	$ 2,839.7	$ 1,036.9	$ 5,010.6	$ (134.3)	$ (3,494.4)	$ 96.7
Balance at , Shares			567.9	567.9
Stock option and incentive plans	39.3				(26.2)	(0.1)		65.6
Currency translation adjustment	(17.7)						(14.7)		(3.0)
Unrealized gain on securities	0.1						0.1
Derivative adjustment, net of reclassification adjustment	(0.3)						(0.3)
Activities of noncontrolling interests	(7.1)				(0.4)				(6.7)
Pension and postretirement healthcare benefits	2.7						2.7
Dividends declared on common stock; $0.25 per share	(106.2)					(106.2)
Net income attributable to ConAgra Foods, Inc.	482.3	144.3				482.3
Balance at	$ 5,748.3		$ 2,839.7	$ 2,839.7	$ 1,010.3	$ 5,386.6	$ (146.5)	$ (3,428.8)	$ 87.0
Balance at , Shares			567.9	567.9