STOCKHOLDERS' EQUITY (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Aug. 25, 2019	Oct. 26, 2018	Aug. 26, 2018
Schedule Of Stockholders Equity Accounts [Line Items]
Balance at beginning of period	$ 7,463.7		$ 3,756.6
Stock option and incentive plans	7.0		9.8
Currency translation adjustment, net	(11.6)		(3.0)
Derivative adjustment, net	(1.8)		(43.4)
Activities of noncontrolling interests	0.5
Pension and postretirement healthcare benefits	(11.4)		(0.5)
Dividends declared on common stock; $0.2125 per share	(103.4)		(83.2)
Net income attributable to Conagra Brands, Inc.	173.8	$ 178.2	178.2
Balance at ending of period	7,516.8		3,815.0
Accounting Standards Update 2016-01
Schedule Of Stockholders Equity Accounts [Line Items]
Adoption of ASU			0.0
Accounting Standards Update 2014-09
Schedule Of Stockholders Equity Accounts [Line Items]
Adoption of ASU			0.5
Common Stock
Schedule Of Stockholders Equity Accounts [Line Items]
Balance at beginning of period	$ 2,921.2		$ 2,839.7
Balance at beginning of period (in shares)	584.2		567.9
Balance at ending of period	$ 2,921.2		$ 2,839.7
Balance at end of period (in shares)	584.2		567.9
Additional Paid-in Capital
Schedule Of Stockholders Equity Accounts [Line Items]
Balance at beginning of period	$ 2,286.0		$ 1,180.0
Stock option and incentive plans	(8.5)		(14.1)
Activities of noncontrolling interests			(0.3)
Balance at ending of period	2,277.5		1,165.6
Retained Earnings
Schedule Of Stockholders Equity Accounts [Line Items]
Balance at beginning of period	5,047.9		4,744.9
Stock option and incentive plans	(0.3)		0.5
Dividends declared on common stock; $0.2125 per share	(103.4)		(83.2)
Net income attributable to Conagra Brands, Inc.	173.8		178.2
Balance at ending of period	5,118.0		4,841.5
Retained Earnings | Accounting Standards Update 2016-01
Schedule Of Stockholders Equity Accounts [Line Items]
Adoption of ASU			0.6
Retained Earnings | Accounting Standards Update 2014-09
Schedule Of Stockholders Equity Accounts [Line Items]
Adoption of ASU			0.5
Accumulated Other Comprehensive Income (Loss)
Schedule Of Stockholders Equity Accounts [Line Items]
Balance at beginning of period	(110.3)		(110.5)
Currency translation adjustment, net	(8.9)		(0.7)
Derivative adjustment, net	(1.8)		(43.4)
Pension and postretirement healthcare benefits	(11.4)		(0.5)
Balance at ending of period	(132.4)		(155.7)
Accumulated Other Comprehensive Income (Loss) | Accounting Standards Update 2016-01
Schedule Of Stockholders Equity Accounts [Line Items]
Adoption of ASU			(0.6)
Treasury Stock
Schedule Of Stockholders Equity Accounts [Line Items]
Balance at beginning of period	(2,760.2)		(4,977.9)
Stock option and incentive plans	16.0		23.3
Balance at ending of period	(2,744.2)		(4,954.6)
Noncontrolling Interests
Schedule Of Stockholders Equity Accounts [Line Items]
Balance at beginning of period	79.1		80.4
Stock option and incentive plans	(0.2)		0.1
Currency translation adjustment, net	(2.7)		(2.3)
Activities of noncontrolling interests	0.5		0.3
Balance at ending of period	$ 76.7		$ 78.5