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								12 Months Ended
	May 31, 2020	Feb. 23, 2020	Nov. 24, 2019	Aug. 25, 2019	May 26, 2019	Feb. 24, 2019	Nov. 25, 2018	Aug. 26, 2018	May 31, 2020	May 26, 2019	May 27, 2018
Net income attributable to Conagra Brands, Inc. common stockholders:
Income from continuing operations attributable to Conagra Brands, Inc. common stockholders									$ 840.1	$ 680.2	$ 794.1
Income (loss) from discontinued operations, net of tax, attributable to Conagra Brands, Inc. common stockholders										(1.9)	14.3
Net income attributable to Conagra Brands, Inc.	$ 201.4	$ 204.4	$ 260.5	$ 173.8	$ 126.5	$ 242.0	$ 131.6	$ 178.2	$ 840.1	$ 678.3	$ 808.4
Weighted average shares outstanding:
Basic weighted average shares outstanding (in shares)									487.3	444.0	403.9
Add: Dilutive effect of stock options, restricted stock unit awards, and other dilutive securities (in shares)									1.3	1.6	3.5
Diluted weighted average shares outstanding (in shares)									488.6	445.6	407.4