STOCKHOLDERS' EQUITY (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Aug. 27, 2017	Aug. 28, 2016
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	$ 4,077.8
Stock option and incentive plans	6.1
Spinoff of Lamb Weston	1.0
Currency translation adjustment, net	32.5
Repurchase of common shares	(300.0)
Unrealized gain on securities	0.2	$ 0.1
Activities of noncontrolling interests	0.8
Dividends declared on common stock; $0.2125 per share	$ (88.3)
Dividends declared on common stock (in dollars per share)	$ 0.2125
Net income attributable to Conagra Brands, Inc.	$ 152.5	$ 186.2
Balance at ending of period	$ 3,882.6
Common Stock
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period (in shares)	567.9
Balance at beginning of period	$ 2,839.7
Balance at end of period (in shares)	567.9
Balance at ending of period	$ 2,839.7
Additional Paid-in Capital
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	1,171.9
Stock option and incentive plans	(12.0)
Balance at ending of period	1,159.9
Retained Earnings
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	4,247.0
Stock option and incentive plans	0.4
Spinoff of Lamb Weston	1.0
Dividends declared on common stock; $0.2125 per share	(88.3)
Net income attributable to Conagra Brands, Inc.	152.5
Balance at ending of period	4,312.6
Accumulated Other Comprehensive Income (Loss)
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	(212.9)
Currency translation adjustment, net	31.5
Unrealized gain on securities	0.2
Balance at ending of period	(181.2)
Treasury Stock
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	(4,054.9)
Stock option and incentive plans	17.7
Repurchase of common shares	(300.0)
Balance at ending of period	(4,337.2)
Noncontrolling Interests
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	87.0
Currency translation adjustment, net	1.0
Activities of noncontrolling interests	0.8
Balance at ending of period	$ 88.8