Note 12 - Stockholders' Equity - Reclassification from Other Comprehensive Income (Loss) to Income (Details) - USD ($) $ 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
Interest expense, net, cash flow hedges		$ (104.2)			$ (94.6)			$ (301.6)	$ (283.7)
Selling, general and administrative expenses		348.8			338.0			1,463.1	993.5
Total before tax		391.8			280.7			734.9	896.5
Income Tax Expense (Benefit), Total		100.1			109.9			237.0	263.8
Net of tax	$ 218.4	341.7	$ 381.9	$ (77.5)	218.4	$ 275.5	$ 235.4	646.1	729.3
Pension and postretirement non-service income		(6.0)			(16.1)			(18.2)	(48.3)
Total before tax		391.8			280.7			734.9	896.5
Income tax expense		100.1			109.9			237.0	263.8
Net income attributable to Conagra Brands, Inc. common stockholders:	$ 218.4	341.7	$ 381.9	$ (77.5)	218.4	$ 275.5	$ 235.4	646.1	729.3
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Interest expense, net, cash flow hedges		(0.9)			(0.8)			(2.5)	(2.3)
Selling, general and administrative expenses		(0.7)			0.4			(0.7)	1.3
Total before tax		(1.6)			(0.4)			(3.2)	(1.0)
Income Tax Expense (Benefit), Total		0.4			0.2			0.9	0.3
Net of tax		(1.2)			(0.2)			(2.3)	(0.7)
Total before tax		(1.6)			(0.4)			(3.2)	(1.0)
Income tax expense		0.4			0.2			0.9	0.3
Net income attributable to Conagra Brands, Inc. common stockholders:		(1.2)			(0.2)			(2.3)	(0.7)
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)			(0.9)			(3.3)	(2.7)
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
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Total before tax		(1.1)			(0.9)			(3.4)	(2.6)
Income Tax Expense (Benefit), Total		0.3			0.3			1.0	0.8
Net of tax		(0.8)			(0.6)			(2.4)	(1.8)
Total before tax		(1.1)			(0.9)			(3.4)	(2.6)
Income tax expense		0.3			0.3			1.0	0.8
Net income attributable to Conagra Brands, Inc. common stockholders:		$ (0.8)			$ (0.6)			$ (2.4)	$ (1.8)