EARNINGS (LOSS) PER SHARE (Average Share Amounts to Compute EPS) (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2016	Feb. 22, 2015	Feb. 28, 2016	Feb. 22, 2015
Net income (loss) available to ConAgra Foods, Inc. common stockholders:
Income from continuing operations attributable to ConAgra Foods, Inc. common stockholders	$ 185.9	$ 210.9	$ 513.3	$ 516.3
Income (loss) from discontinued operations, net of tax, attributable to ConAgra Foods, Inc. common stockholders	18.7	(1,165.0)	(1,307.9)	(978.1)
Net income (loss) attributable to ConAgra Foods, Inc.	204.6	(954.1)	(794.6)	(461.8)
Less: Increase in redemption value of noncontrolling interests in excess of earnings allocated	3.5	0.4	4.4	1.3
Net income (loss) available to ConAgra Foods, Inc. common stockholders	$ 201.1	$ (954.5)	$ (799.0)	$ (463.1)
Weighted average shares outstanding:
Basic weighted average shares outstanding (in shares)	435.7	427.1	433.3	425.5
Add: Dilutive effect of stock options, restricted stock unit awards, and other dilutive securities (in shares)	3.9	5.2	4.3	5.3
Diluted weighted average shares outstanding (in shares)	439.6	432.3	437.6	430.8