Note 14 - Stockholders' Equity - Reconciliation of Stockholders' Equity Accounts (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended				6 Months Ended
	Nov. 26, 2023	Aug. 27, 2023	Nov. 27, 2022	Aug. 28, 2022	Nov. 26, 2023	Nov. 27, 2022
Balance	$ 8,955.1	$ 8,807.3	$ 8,576.7	$ 8,862.2	$ 8,807.3	$ 8,862.2
Stock option and incentive plans	6.6	(16.2)	39.6	14.9
Currency translation adjustments	(6.3)	10.6	(8.2)	(13.6)
Derivative adjustments	0.8	1.6	6.6	(2.1)
Activities of noncontrolling interests		0.2	0.3
Pension and postretirement healthcare benefits	(1.0)	(0.8)	(1.4)	1.4
Dividends declared on common stock	(167.2)	(167.3)	(157.8)	(158.6)
Net income attributable to Conagra Brands, Inc. common stockholders:	286.2	319.7	381.9	(77.5)	605.9	304.4
Repurchase of common shares			(100.0)	(50.0)
Balance	$ 9,074.2	$ 8,955.1	$ 8,737.7	$ 8,576.7	$ 9,074.2	$ 8,737.7
Common Stock [Member]
Balance (in shares)	584.2	584.2	584.2	584.2	584.2	584.2
Balance	$ 2,921.2	$ 2,921.2	$ 2,921.2	$ 2,921.2	$ 2,921.2	$ 2,921.2
Balance (in shares)	584.2	584.2	584.2	584.2	584.2	584.2
Balance	$ 2,921.2	$ 2,921.2	$ 2,921.2	$ 2,921.2	$ 2,921.2	$ 2,921.2
Additional Paid-in Capital [Member]
Balance	2,334.0	2,376.9	2,323.0	2,324.6	2,376.9	2,324.6
Stock option and incentive plans	5.6	(42.9)	37.9	(1.6)
Balance	2,339.6	2,334.0	2,360.9	2,323.0	2,339.6	2,360.9
Retained Earnings [Member]
Balance	6,752.9	6,599.4	6,314.8	6,550.7	6,599.4	6,550.7
Stock option and incentive plans	(0.4)	1.1	(2.4)	0.2
Dividends declared on common stock	(167.2)	(167.3)	(157.8)	(158.6)
Net income attributable to Conagra Brands, Inc. common stockholders:		319.7	381.9	(77.5)
Balance	6,871.5	6,752.9	6,536.5	6,314.8	6,871.5	6,536.5
AOCI Attributable to Parent [Member]
Balance	(32.9)	(44.4)	(23.4)	(11.2)	(44.4)	(11.2)
Currency translation adjustments	(5.6)	10.7	(6.5)	(11.5)
Derivative adjustments	0.8	1.6	6.6	(2.1)
Pension and postretirement healthcare benefits	(1.0)	(0.8)	(1.3)	1.4
Balance	(38.7)	(32.9)	(24.6)	(23.4)	(38.7)	(24.6)
Treasury Stock, Common [Member]
Balance	(3,090.7)	(3,116.3)	(3,031.3)	(2,997.6)	(3,116.3)	(2,997.6)
Stock option and incentive plans	1.1	25.6	3.6	16.3
Repurchase of common shares				(50.0)
Balance	(3,089.6)	(3,090.7)	(3,127.7)	(3,031.3)	(3,089.6)	(3,127.7)
Noncontrolling Interest [Member]
Balance	70.6	70.5	72.4	74.5	70.5	74.5
Stock option and incentive plans	0.3		0.5
Currency translation adjustments	(0.7)	(0.1)	(1.7)	(2.1)
Activities of noncontrolling interests		0.2	0.3
Pension and postretirement healthcare benefits			(0.1)
Balance	$ 70.2	$ 70.6	$ 71.4	$ 72.4	$ 70.2	$ 71.4