STOCKHOLDERS' EQUITY (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Aug. 26, 2018	Aug. 27, 2017	May 27, 2018
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	$ 3,756.6
Stock option and incentive plans	9.8
Currency translation adjustment, net	(3.0)
Derivative adjustment, net	(43.4)	$ 0.0
Activities of noncontrolling interests	0.0
Pension and postretirement healthcare benefits	(0.5)
Dividends declared on common stock; $0.2125 per share	$ (83.2)
Dividends declared on common stock (in dollars per share)	$ 0.2125
Net income attributable to Conagra Brands, Inc.	$ 178.2	$ 152.5
Balance at ending of period	$ 3,815.0
Accounting Standards Update 2016-01
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU			$ 0.0
Accounting Standards Update 2014-09
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU			0.5
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	1,180.0
Stock option and incentive plans	(14.1)
Activities of noncontrolling interests	(0.3)
Balance at ending of period	1,165.6
Retained Earnings
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	4,744.9
Stock option and incentive plans	0.5
Dividends declared on common stock; $0.2125 per share	(83.2)
Net income attributable to Conagra Brands, Inc.	178.2
Balance at ending of period	4,841.5
Retained Earnings | Accounting Standards Update 2016-01
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU			0.6
Retained Earnings | Accounting Standards Update 2014-09
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU			0.5
Accumulated Other Comprehensive Income (Loss)
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	(110.5)
Currency translation adjustment, net	(0.7)
Derivative adjustment, net	(43.4)
Pension and postretirement healthcare benefits	(0.5)
Balance at ending of period	(155.7)
Accumulated Other Comprehensive Income (Loss) | Accounting Standards Update 2016-01
Conagra Brands, Inc. Stockholders' Equity
Adoption of ASU			$ (0.6)
Treasury Stock
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	(4,977.9)
Stock option and incentive plans	23.3
Balance at ending of period	(4,954.6)
Noncontrolling Interests
Conagra Brands, Inc. Stockholders' Equity
Balance at beginning of period	80.4
Stock option and incentive plans	0.1
Currency translation adjustment, net	(2.3)
Activities of noncontrolling interests	0.3
Balance at ending of period	$ 78.5