BUSINESS SEGMENTS AND RELATED INFORMATION - Schedule of Segment Operations (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Feb. 28, 2021	Nov. 29, 2020	Aug. 30, 2020	Feb. 23, 2020	Nov. 24, 2019	Aug. 25, 2019	Feb. 28, 2021	Feb. 23, 2020
Net sales
Total net sales	$ 2,771.1			$ 2,555.0			$ 8,445.2	$ 7,766.5
Operating profit
Total operating profit	545.4			439.6			1,775.0	1,318.6
Equity method investment earnings	21.5			10.4			51.0	50.3
General corporate expense	96.7			75.1			285.2	262.3
Pension and postretirement non-service income	(13.7)			(16.4)			(41.2)	(37.2)
Interest expense, net	100.6			117.7			322.0	361.8
Income tax expense	101.6			68.9			269.0	141.5
Net income	281.7			204.7			991.0	640.5
Less: Net income attributable to noncontrolling interests	0.3			0.3			1.7	1.8
Net income attributable to Conagra Brands, Inc.	281.4	$ 378.9	$ 329.0	204.4	$ 260.5	$ 173.8	989.3	638.7
Frozen
Net sales
Total net sales	1,013.2			907.4			2,951.9	2,635.6
Other Shelf-stable
Net sales
Total net sales	698.7			639.1			2,207.9	1,921.0
Snacks
Net sales
Total net sales	434.4			383.8			1,344.7	1,222.0
Foodservice
Net sales
Total net sales	194.0			234.4			601.2	759.7
International
Net sales
Total net sales	240.9			220.9			709.7	659.6
Refrigerated
Net sales
Total net sales	189.9			169.4			629.8	568.6
Grocery & Snacks
Net sales
Total net sales	1,133.1			1,022.9			3,552.6	3,143.0
Operating profit
Total operating profit	290.2			199.4			890.2	614.8
Refrigerated & Frozen
Net sales
Total net sales	1,203.1			1,076.8			3,581.7	3,204.2
Operating profit
Total operating profit	214.6			190.7			719.0	533.7
International
Net sales
Total net sales	240.9			220.9			709.7	659.6
Operating profit
Total operating profit	27.8			22.3			105.8	73.5
Foodservice
Net sales
Total net sales	194.0			234.4			601.2	759.7
Operating profit
Total operating profit	$ 12.8			$ 27.2			$ 60.0	$ 96.6