Note 12 - Stockholders' Equity - Reconciliation of Stockholders' Equity Accounts (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended						9 Months Ended
	Feb. 27, 2022	Feb. 26, 2023	Nov. 27, 2022	Aug. 28, 2022	Feb. 27, 2022	Nov. 28, 2021	Aug. 29, 2021	Feb. 26, 2023	Feb. 27, 2022
Balance		$ 8,737.7	$ 8,576.7	$ 8,862.2	$ 8,756.9	$ 8,635.9	$ 8,631.4	$ 8,862.2	$ 8,631.4
Stock option and incentive plans	$ 16.1	(16.2)	(39.6)	14.9		11.9	(14.8)
Currency translation adjustments	10.7	4.3	(8.2)	(13.6)		(17.7)	(15.7)
Repurchase of common shares			(100.0)	(50.0)			(50.0)
Derivative adjustments	1.3	(3.9)	(6.6)	(2.1)		(1.4)	(2.1)
Pension and postretirement healthcare benefits	(0.6)	(0.8)	(1.4)	1.4		(0.6)	1.3
Dividends declared on common stock	(150.0)	(157.4)	(157.8)	(158.6)		(149.9)	(149.9)
Net loss attributable to Conagra Brands, Inc.	218.4	341.7	381.9	(77.5)	218.4	275.5	235.4	646.1	729.3
Stock option and incentive plans	(16.1)	16.2	39.6	(14.9)		(11.9)	14.8
Derivative adjustments	(1.3)	3.9	6.6	2.1		1.4	2.1
Activities of noncontrolling interests	0.5	0.5	0.3			0.4	0.3
Stock option and incentive plans	16.1	(16.2)	(39.6)	14.9		11.9	(14.8)
Balance	$ 8,853.3	$ 8,938.3	$ 8,737.7	$ 8,576.7	$ 8,853.3	$ 8,756.9	$ 8,635.9	$ 8,938.3	$ 8,853.3
Common Stock [Member]
Balance (in shares)		584.2	584.2	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	$ 2,921.2	$ 2,921.2
Balance (in shares)	584.2	584.2	584.2	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	$ 2,921.2	$ 2,921.2	$ 2,921.2
Additional Paid-in Capital [Member]
Balance		2,360.9	2,323.0	2,324.6	2,317.1	2,305.0	2,342.1	2,324.6	2,342.1
Stock option and incentive plans	11.1	(7.3)	(37.9)	(1.6)		12.1	(37.1)
Stock option and incentive plans	(11.1)	7.3	37.9	1.6		(12.1)	37.1
Stock option and incentive plans	11.1	(7.3)	(37.9)	(1.6)		12.1	(37.1)
Balance	2,328.2	2,368.2	2,360.9	2,323.0	2,328.2	2,317.1	2,305.0	2,368.2	2,328.2
Retained Earnings [Member]
Balance		6,536.5	6,314.8	6,550.7	6,473.3	6,348.3	6,262.6	6,550.7	6,262.6
Stock option and incentive plans	(0.5)	0.8	2.4	0.2		(0.6)	0.2
Pension and postretirement healthcare benefits	(0.6)
Dividends declared on common stock	(150.0)	(157.4)	(157.8)	(158.6)		(149.9)	(149.9)
Net loss attributable to Conagra Brands, Inc.	218.4		381.9	(77.5)			235.4
Stock option and incentive plans	0.5	(0.8)	(2.4)	(0.2)		0.6	(0.2)
Stock option and incentive plans	(0.5)	0.8	2.4	0.2		(0.6)	0.2
Balance	6,541.2	6,720.0	6,536.5	6,314.8	6,541.2	6,473.3	6,348.3	6,720.0	6,541.2
AOCI Attributable to Parent [Member]
Balance		(24.6)	(23.4)	(11.2)	(24.8)	(9.4)	5.8	(11.2)	5.8
Currency translation adjustments	10.8	5.8	(6.5)	(11.5)		(16.2)	(14.4)
Derivative adjustments	1.3	(3.9)	(6.6)	(2.1)		(1.4)	(2.1)
Pension and postretirement healthcare benefits		(0.8)	(1.3)	1.4		(0.6)	1.3
Derivative adjustments	(1.3)	3.9	6.6	2.1		1.4	2.1
Balance	(13.3)	(23.5)	(24.6)	(23.4)	(13.3)	(24.8)	(9.4)	(23.5)	(13.3)
Treasury Stock [Member]
Balance		(3,127.7)	(3,031.3)	(2,997.6)	(3,007.8)	(3,008.1)	(2,979.9)	(2,997.6)	(2,979.9)
Stock option and incentive plans	5.1	(8.2)	(3.6)	16.3		0.3	21.8
Repurchase of common shares			(100.0)	(50.0)			(50.0)
Stock option and incentive plans	(5.1)	8.2	3.6	(16.3)		(0.3)	(21.8)
Stock option and incentive plans	5.1	(8.2)	(3.6)	16.3		0.3	21.8
Balance	(3,002.7)	(3,119.5)	(3,127.7)	(3,031.3)	(3,002.7)	(3,007.8)	(3,008.1)	(3,119.5)	(3,002.7)
Noncontrolling Interest [Member]
Balance		71.4	72.4	74.5	77.9	78.9	79.6	74.5	79.6
Stock option and incentive plans	0.4	(1.5)	(0.5)			0.1	0.3
Currency translation adjustments	(0.1)	(1.5)	(1.7)	(2.1)		(1.5)	(1.3)
Pension and postretirement healthcare benefits			(0.1)
Stock option and incentive plans	(0.4)	1.5	0.5			(0.1)	(0.3)
Activities of noncontrolling interests	0.5	0.5	0.3				0.3
Stock option and incentive plans	0.4	(1.5)	(0.5)			0.1	0.3
Balance	$ 78.7	$ 71.9	$ 71.4	$ 72.4	$ 78.7	$ 77.9	$ 78.9	$ 71.9	$ 78.7