Supplemental Information (Schedule of certain Consolidated Balance Sheet accounts) (Details) - USD ($) $ in Millions		May 27, 2018	May 28, 2017	May 29, 2016	May 31, 2015
Receivables [Abstract]
Customers		$ 1,712.6	$ 1,454.4
Less allowance for doubtful accounts		(28.4)	(24.3)
Total		1,684.2	1,430.1
Inventories [Abstract]
Raw materials and packaging		400.0	395.4
Finished goods		1,364.2	1,224.3
Grain		91.2	73.0
Excess of FIFO over LIFO cost	[1]	(213.2)	(209.1)
Total		1,642.2	1,483.6
LIFO Inventory Amount		832.2	893.8
Prepaid Expenses and Other Current Assets [Abstract]
Other receivables		174.4	163.7
Prepaid expenses		165.6	168.9
Derivative receivables, primarily commodity-related		40.5	35.0
Grain contracts		7.1	2.7
Miscellaneous		10.7	11.3
Total		398.3	381.6
Land, Buildings and Equipment [Abstract]
Land		77.7	79.8
Buildings		2,396.3	2,249.2
Equipment		6,236.6	6,095.9
Capitalized software		593.6	545.4
Construction in progress		692.9	553.0
Total land, buildings, and equipment		10,003.2	9,526.6
Less accumulated depreciation		(5,956.0)	(5,838.9)
Total		4,047.2	3,687.7
Other Assets [Abstract]
Investments in and advances to joint ventures		499.6	505.3
Pension assets		309.9	144.9
Life insurance		26.9	25.6
Miscellaneous		106.6	110.1
Total		943.0	785.9
Other Current Liabilities [Abstract]
Accrued trade and consumer promotions		499.6	482.6
Accrued payroll		347.0	326.6
Dividends payable		17.5	21.5
Accrued taxes		94.8	58.0
Accrued interest, including interest rate swaps		107.7	83.8
Grains contracts		1.2	5.6
Restructuring and other exit costs reserve		66.8	85.0	$ 76.6	$ 120.8
Derivative payable		8.3	18.1
Miscellaneous		302.9	291.0
Total		1,445.8	1,372.2
Other Noncurrent Liabilities [Abstract]
Accrued compensation and benefits, including obligations for underfunded other postretirement benefit and postemployment benefit plans		999.4	1,249.7
Accrued taxes		265.3	162.3
Miscellaneous		76.3	111.1
Total		1,341.0	1,523.1
Buildings [Member]
Land, Buildings and Equipment [Abstract]
Capital leased assets		0.3	0.3
Equipment [Member]
Land, Buildings and Equipment [Abstract]
Capital leased assets		$ 5.8	$ 3.0

[1] Inventories of $832.2 million as of May 27, 2018 , and $893.8 million as of May 28, 2017 , were valued at LIFO. The difference bet ween replacement cost and the stated LIFO inventory valu e is not materially different from the reserve for the LIFO valuation meth od.