EARNINGS (LOSS) PER SHARE - Reconciliation of Income and Average Share Amounts Used to Compute Basic and Diluted Earnings (Loss) Per Share (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Aug. 28, 2016	Aug. 30, 2015
Net income (loss) available to ConAgra Foods, Inc. common stockholders:
Income from continuing operations attributable to ConAgra Foods, Inc. common stockholders	$ 184.7	$ 165.7
Income (loss) from discontinued operations, net of tax, attributable to ConAgra Foods, Inc. common stockholders	1.5	(1,319.8)
Net income (loss) attributable to ConAgra Foods, Inc.	186.2	(1,154.1)
Less: Increase in redemption value of noncontrolling interests in excess of earnings allocated	0.5	0.4
Net income (loss) available to ConAgra Foods, Inc. common stockholders	$ 185.7	$ (1,154.5)
Weighted average shares outstanding:
Basic weighted average shares outstanding (in shares)	439.0	430.7
Add: Dilutive effect of stock options, restricted stock unit awards, and other dilutive securities (in shares)	3.7	5.0
Diluted weighted average shares outstanding (in shares)	442.7	435.7