Consolidated Statements of Common Stockholders' Equity (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	May 27, 2012	Feb. 26, 2012	Nov. 27, 2011	Aug. 28, 2011	May 29, 2011	Feb. 27, 2011	Nov. 28, 2010	Aug. 29, 2010	May 27, 2012	May 29, 2011	May 30, 2010
Beginning balance				$ 4,676.7					$ 4,676.7	$ 4,897.1	$ 4,689.1
Stock option and incentive plans									255.5	105.0	110.7
Currency translation adjustment, net of reclassification adjustment									(56.4)	45.7	(3.7)
Repurchase of common shares									(352.4)	(825.0)	(100.0)
Unrealized loss on securities									(0.1)	(0.1)
Derivative adjustment, net of reclassification adjustment									(89.1)	(7.2)	0.2
Activities of noncontrolling interests									(0.2)	0.1	3.0
Pension and postretirement healthcare liabilities, net of tax									(66.7)	23.6	(65.8)
Dividends declared on common stock; $0.79 per share,$0.89 per share,$0.95 per share.									(391.8)	(380.1)	(349.9)
Net income (loss) attributable to ConAgra Foods, Inc.	(86.2)	280.1	180.2	93.8	250.1	216.6	202.7	148.2	467.9	817.6	613.5
Ending Balance	4,536.0				4,676.7				4,536.0	4,676.7	4,897.1
Common Stock
Beginning balance											2,835.9
Opening balance, shares											567.2
Stock option and incentive plans											3.8
Stock option and incentive plans, shares											0.7
Ending Balance	2,839.7				2,839.7				2,839.7	2,839.7	2,839.7
Ending Balance, shares	567.9				567.9				567.9	567.9	567.9
Additional Paid-in Capital
Beginning balance				899.1					899.1	897.5	884.4
Stock option and incentive plans									3.9	3.5	15.1
Activities of noncontrolling interests									(1.5)	(1.9)	(2.0)
Ending Balance	901.5				899.1				901.5	899.1	897.5
Retained Earnings
Beginning balance				4,690.3					4,690.3	4,253.2	3,990.9
Stock option and incentive plans									(1.3)	(0.4)	(1.3)
Dividends declared on common stock; $0.79 per share,$0.89 per share,$0.95 per share.									(391.8)	(380.1)	(349.9)
Net income (loss) attributable to ConAgra Foods, Inc.									467.9	817.6	613.5
Ending Balance	4,765.1				4,690.3				4,765.1	4,690.3	4,253.2
Accumulated Other Comprehensive Income (Loss)
Beginning balance				(91.2)					(91.2)	(153.2)	(83.9)
Currency translation adjustment, net of reclassification adjustment									(52.0)	45.7	(3.7)
Unrealized loss on securities									(0.1)	(0.1)
Derivative adjustment, net of reclassification adjustment									(89.1)	(7.2)	0.2
Pension and postretirement healthcare liabilities, net of tax									(66.7)	23.6	(65.8)
Ending Balance	(299.1)				(91.2)				(299.1)	(91.2)	(153.2)
Treasury Stock
Beginning balance				(3,668.2)					(3,668.2)	(2,945.1)	(2,938.2)
Stock option and incentive plans									252.9	101.9	93.1
Repurchase of common shares									(352.4)	(825.0)	(100.0)
Ending Balance	(3,767.7)				(3,668.2)				(3,767.7)	(3,668.2)	(2,945.1)
Noncontrolling Interest
Beginning balance				7.0					7.0	5.0	0
Currency translation adjustment, net of reclassification adjustment									(4.4)
Activities of noncontrolling interests									1.3	2.0	5.0
Ending Balance	$ 96.5				$ 7.0				$ 96.5	$ 7.0	$ 5.0