Note 13 - Stockholders' Equity - Reconciliation of Stockholders' Equity Accounts (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Aug. 28, 2022	Aug. 29, 2021
Balance	$ 8,862.2	$ 8,631.4
Stock option and incentive plans	14.9	(14.8)
Currency translation adjustments	(13.6)	(15.7)
Repurchase of common shares	(50.0)	(50.0)
Derivative adjustments	(2.1)	(2.1)
Pension and postretirement healthcare benefits	1.4	1.3
Dividends declared on common stock	(158.6)	(149.9)
Net income (loss) attributable to Conagra Brands, Inc. common stockholders:	(77.5)	235.4
Activities of noncontrolling interests		0.3
Balance	$ 8,576.7	$ 8,635.9
Common Stock [Member]
Balance (in shares)	584.2	584.2
Balance	$ 2,921.2	$ 2,921.2
Stock option and incentive plans
Currency translation adjustments
Repurchase of common shares
Derivative adjustments
Pension and postretirement healthcare benefits
Dividends declared on common stock
Net income (loss) attributable to Conagra Brands, Inc. common stockholders:
Activities of noncontrolling interests
Balance (in shares)	584.2	584.2
Balance	$ 2,921.2	$ 2,921.2
Additional Paid-in Capital [Member]
Balance	2,324.6	2,342.1
Stock option and incentive plans	(1.6)	(37.1)
Currency translation adjustments
Repurchase of common shares
Derivative adjustments
Pension and postretirement healthcare benefits
Dividends declared on common stock
Net income (loss) attributable to Conagra Brands, Inc. common stockholders:
Activities of noncontrolling interests
Balance	2,323.0	2,305.0
Retained Earnings [Member]
Balance	6,550.7	6,262.6
Stock option and incentive plans	0.2	0.2
Currency translation adjustments
Repurchase of common shares
Derivative adjustments
Pension and postretirement healthcare benefits
Dividends declared on common stock	(158.6)	(149.9)
Net income (loss) attributable to Conagra Brands, Inc. common stockholders:	(77.5)	235.4
Activities of noncontrolling interests
Balance	6,314.8	6,348.3
AOCI Attributable to Parent [Member]
Balance	(11.2)	5.8
Stock option and incentive plans
Currency translation adjustments	(11.5)	(14.4)
Repurchase of common shares
Derivative adjustments	(2.1)	(2.1)
Pension and postretirement healthcare benefits	1.4	1.3
Dividends declared on common stock
Net income (loss) attributable to Conagra Brands, Inc. common stockholders:
Activities of noncontrolling interests
Balance	(23.4)	(9.4)
Treasury Stock [Member]
Balance	(2,997.6)	(2,979.9)
Stock option and incentive plans	16.3	21.8
Currency translation adjustments
Repurchase of common shares	(50.0)	(50.0)
Derivative adjustments
Pension and postretirement healthcare benefits
Dividends declared on common stock
Net income (loss) attributable to Conagra Brands, Inc. common stockholders:
Activities of noncontrolling interests
Balance	(3,031.3)	(3,008.1)
Noncontrolling Interest [Member]
Balance	74.5	79.6
Stock option and incentive plans		0.3
Currency translation adjustments	(2.1)	(1.3)
Repurchase of common shares
Derivative adjustments
Pension and postretirement healthcare benefits
Dividends declared on common stock
Net income (loss) attributable to Conagra Brands, Inc. common stockholders:
Activities of noncontrolling interests		0.3
Balance	$ 72.4	$ 78.9