EARNINGS 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		9 Months Ended
	Feb. 25, 2018	Feb. 26, 2017	Feb. 25, 2018	Feb. 26, 2017
Net income available to Conagra Brands, Inc. common stockholders:
Income from continuing operations attributable to Conagra Brands, Inc. common stockholders	$ 348.3	$ 179.0	$ 724.2	$ 391.1
Income from discontinued operations, net of tax, attributable to Conagra Brands, Inc. common stockholders	14.5	0.7	14.6	96.9
Net income attributable to Conagra Brands, Inc.	362.8	179.7	738.8	488.0
Less: Increase in redemption value of noncontrolling interests in excess of earnings allocated	0.0	0.0	0.0	0.8
Net income available to Conagra Brands, Inc. common stockholders	$ 362.8	$ 179.7	$ 738.8	$ 487.2
Weighted average shares outstanding:
Basic weighted average shares outstanding (in shares)	399.1	431.7	407.3	436.0
Add: Dilutive effect of stock options, restricted stock unit awards, and other dilutive securities (in shares)	3.4	4.7	3.8	4.0
Diluted weighted average shares outstanding (in shares)	402.5	436.4	411.1	440.0