Note 12 - Stockholders' Equity - Reclassification from Other Comprehensive Income (Loss) to Income (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Nov. 27, 2022	Aug. 28, 2022	Nov. 28, 2021	Aug. 29, 2021	Nov. 27, 2022	Nov. 28, 2021
Interest expense, net, cash flow hedges	$ (100.3)		$ (94.9)		$ (197.4)	$ (189.1)
Selling, general and administrative expenses	372.7		345.4		1,114.3	655.5
Total before tax	455.4		330.6		343.1	615.8
Income Tax Expense (Benefit), Total	122.5		84.2		136.9	153.9
Net of tax	381.9	$ (77.5)	275.5	$ 235.4	304.4	510.9
Pension and postretirement non-service income	(6.1)		(16.1)		(12.2)	(32.2)
Total before tax	455.4		330.6		343.1	615.8
Income tax expense	122.5		84.2		136.9	153.9
Net income attributable to Conagra Brands, Inc. common stockholders:	381.9	$ (77.5)	275.5	$ 235.4	304.4	510.9
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Interest expense, net, cash flow hedges	(0.8)		(0.7)		(1.6)	(1.5)
Selling, general and administrative expenses	(0.2)		0.4		0.0	0.9
Total before tax	(1.0)		(0.3)		(1.6)	(0.6)
Income Tax Expense (Benefit), Total	0.3		0.0		0.5	0.1
Net of tax	(0.7)		(0.3)		(1.1)	(0.5)
Total before tax	(1.0)		(0.3)		(1.6)	(0.6)
Income tax expense	0.3		0.0		0.5	0.1
Net income attributable to Conagra Brands, Inc. common stockholders:	(0.7)		(0.3)		(1.1)	(0.5)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member]
Pension and postretirement non-service income	(0.1)		0.1		(0.1)	0.1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member]
Pension and postretirement non-service income	(1.1)		(1.0)		(2.2)	(1.8)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Total before tax	(1.2)		(0.9)		(2.3)	(1.7)
Income Tax Expense (Benefit), Total	0.3		0.3		0.7	0.5
Net of tax	(0.9)		(0.6)		(1.6)	(1.2)
Total before tax	(1.2)		(0.9)		(2.3)	(1.7)
Income tax expense	0.3		0.3		0.7	0.5
Net income attributable to Conagra Brands, Inc. common stockholders:	$ (0.9)		$ (0.6)		$ (1.6)	$ (1.2)