Note 13 - Stockholders' Equity - Reconciliation of Stockholders' Equity Accounts (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Aug. 27, 2023	Aug. 28, 2022
Balance	$ 8,807.3	$ 8,862.2
Stock option and incentive plans	(16.2)	14.9
Currency translation adjustments	10.6	(13.6)
Derivative adjustments	1.6	(2.1)
Activities of noncontrolling interests	0.2
Pension and postretirement healthcare benefits	(0.8)	1.4
Dividends declared on common stock	(167.3)	(158.6)
Net income (loss) attributable to Conagra Brands, Inc. common stockholders:	319.7	(77.5)
Repurchase of common shares		(50.0)
Balance	$ 8,955.1	$ 8,576.7
Common Stock [Member]
Balance (in shares)	584.2	584.2
Balance	$ 2,921.2	$ 2,921.2
Balance (in shares)	584.2	584.2
Balance	$ 2,921.2	$ 2,921.2
Additional Paid-in Capital [Member]
Balance	2,376.9	2,324.6
Stock option and incentive plans	(42.9)	(1.6)
Balance	2,334.0	2,323.0
Retained Earnings [Member]
Balance	6,599.4	6,550.7
Stock option and incentive plans	1.1	0.2
Dividends declared on common stock	(167.3)	(158.6)
Net income (loss) attributable to Conagra Brands, Inc. common stockholders:	319.7	(77.5)
Balance	6,752.9	6,314.8
AOCI Attributable to Parent [Member]
Balance	(44.4)	(11.2)
Currency translation adjustments	10.7	(11.5)
Derivative adjustments	1.6	(2.1)
Pension and postretirement healthcare benefits	(0.8)	1.4
Balance	(32.9)	(23.4)
Treasury Stock, Common [Member]
Balance	(3,116.3)	(2,997.6)
Stock option and incentive plans	25.6	16.3
Repurchase of common shares		(50.0)
Balance	(3,090.7)	(3,031.3)
Noncontrolling Interest [Member]
Balance	70.5	74.5
Stock option and incentive plans
Currency translation adjustments	(0.1)	(2.1)
Activities of noncontrolling interests	0.2
Balance	$ 70.6	$ 72.4