Quarterly Financial Data (Details) (USD $) In Millions, except Per Share data	3 Months Ended								12 Months Ended
	May 29, 2011	Feb. 27, 2011	Nov. 28, 2010	Aug. 29, 2010	May 30, 2010	Feb. 27, 2010	Nov. 29, 2009	Aug. 30, 2009	May 29, 2011	May 30, 2010	May 31, 2009
Quarterly Financial Data [Abstract]
Net sales	$ 3,210.0	$ 3,141.3	$ 3,147.5	$ 2,804.3	$ 3,047.5	$ 3,015.0	$ 3,083.2	$ 2,869.2	$ 12,303.1	$ 12,014.9	$ 12,348.6
Gross profit	704.9	797.3	760.0	651.3	737.0	778.2	841.6	704.4
Income (loss) from discontinued operations, net of tax	(4.5)	(10.6)	0.6	3.0	(32.3)	7.8	1.9	3.3	(11.5)	(19.3)	363.8
Net income available to ConAgra Foods, Inc	$ 254.9	$ 214.8	$ 200.9	$ 146.4	$ 90.6	$ 229.6	$ 239.7	$ 165.9	$ 817.0	$ 725.8	$ 978.4
Basic earnings per share:
Income from continuing operations attributable to ConAgra Foods, Inc. common stockholders	$ 0.63	$ 0.53	$ 0.46	$ 0.32	$ 0.28	$ 0.50	$ 0.54	$ 0.37	$ 1.92	$ 1.68	$ 1.36
Income (loss) from discontinued operations attributable to ConAgra Foods, Inc. common stockholders	$ (0.01)	$ (0.03)		$ 0.01	$ (0.08)	$ 0.02			$ (0.02)	$ (0.05)	$ 0.80
Net income attributable to ConAgra Foods, Inc. common stockholders	$ 0.62	$ 0.50	$ 0.46	$ 0.33	$ 0.20	$ 0.52	$ 0.54	$ 0.37	$ 1.90	$ 1.63	$ 2.16
Diluted earnings per share:
Income from continuing operations attributable to ConAgra Foods, Inc. common stockholders	$ 0.62	$ 0.52	$ 0.45	$ 0.32	$ 0.27	$ 0.49	$ 0.53	$ 0.36	$ 1.90	$ 1.66	$ 1.35
Income (loss) from discontinued operations attributable to ConAgra Foods, Inc. common stockholders	$ (0.01)	$ (0.02)		$ 0.01	$ (0.07)	$ 0.02	$ 0.01	$ 0.01	$ (0.02)	$ (0.04)	$ 0.80
Net income attributable to ConAgra Foods, Inc. common stockholders	$ 0.61	$ 0.50	$ 0.45	$ 0.33	$ 0.20	$ 0.51	$ 0.54	$ 0.37	$ 1.88	$ 1.62	$ 2.15
Dividends declared per common share	$ 0.23	$ 0.23	$ 0.23	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.19	$ 0.89	$ 0.79	$ 0.76
Share Price:
High	$ 25.58	$ 23.58	$ 22.95	$ 25.23	$ 26.28	$ 24.64	$ 22.56	$ 20.45
Low	$ 22.48	$ 21.48	$ 21.14	$ 21.36	$ 23.58	$ 21.83	$ 19.92	$ 18.51