Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Feb. 28, 2021	Feb. 23, 2020	Feb. 28, 2021	Feb. 23, 2020	May 31, 2020
Cash flows from operating activities:
Net income	$ 281.7	$ 204.7	$ 991.0	$ 640.5
Adjustments to reconcile net income to net cash flows from operating activities:
Depreciation and amortization			289.6	292.5
Asset impairment charges			4.2	113.5
Loss on extinguishment of debt			68.7	0.8
Loss (gain) on divestitures			(55.0)	2.2
Equity method investment earnings in excess of distributions			(19.3)	(15.8)
Stock-settled share-based payments expense			41.1	29.0
Contributions to pension plans			(23.7)	(11.0)
Pension benefit			(29.2)	(25.8)
Other items			12.6	11.3
Change in operating assets and liabilities excluding effects of business acquisitions and dispositions:
Receivables			18.5	(37.2)
Inventories			(206.7)	(104.6)
Deferred income taxes and income taxes payable, net			15.9	(33.3)
Prepaid expenses and other current assets			(27.9)	(14.6)
Accounts payable			(24.1)	116.4
Accrued payroll			(21.4)	(40.0)
Other accrued liabilities			1.8	(17.4)
Deferred employer payroll taxes			33.9	0.0
Net cash flows from operating activities			1,070.0	906.5
Cash flows from investing activities:
Additions to property, plant and equipment			(396.7)	(265.3)
Proceeds from divestitures, net of cash divested			112.2	191.4
Sale of property, plant and equipment			1.1	8.7
Purchase of marketable securities			(6.8)	(37.9)
Sale of marketable securities			8.3	43.1
Other items			0.0	0.1
Net cash flows from investing activities			(281.9)	(59.9)
Cash flows from financing activities:
Issuances of commercial paper, maturities greater than 90 days			298.6	0.0
Repayment of commercial paper, maturities greater than 90 days			(49.9)	0.0
Net issuances (repayments) of other short-term borrowings			478.9	(0.1)
Issuance of long-term debt			988.2	0.0
Repayment of long-term debt			(2,312.1)	(665.9)
Debt issuance costs			(6.2)	0.0
Repurchase of Conagra Brands, Inc. common shares			(298.1)	0.0
Payment of intangible asset financing arrangement			(12.9)	(13.6)
Cash dividends paid			(341.7)	(310.1)
Exercise of stock options and issuance of other stock awards, including tax withholdings			(8.4)	4.3
Other items			0.0	0.8
Net cash flows from financing activities			(1,263.6)	(984.6)
Effect of exchange rate changes on cash and cash equivalents and restricted cash			2.9	0.4
Net change in cash and cash equivalents and restricted cash			(472.6)	(137.6)
Cash and cash equivalents and restricted cash at beginning of period			554.3	237.6	$ 237.6
Cash and cash equivalents and restricted cash at end of period	$ 81.7	$ 100.0	$ 81.7	$ 100.0	$ 554.3