Business Segment and Geographic Information (Schedule of operating segment results) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Nov. 28, 2021	Nov. 29, 2020	Nov. 28, 2021	Nov. 29, 2020
Segment Reporting Information [Line Items]
Net sales	$ 5,024.0	$ 4,719.4	$ 9,563.9	$ 9,083.4
Operating profit	800.1	916.6	1,644.4	1,770.3
Restructuring, impairment, and other exit costs	2.3	0.4	(2.0)	0.9
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	5,024.0	4,719.4	9,563.9	9,083.4
Operating profit	934.2	965.4	1,830.4	1,894.0
Unallocated Corporate Items [Member]
Segment Reporting Information [Line Items]
Operating profit	131.8	48.4	188.0	122.8
North America Retail [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	2,975.5	2,921.5	5,614.4	5,628.5
Operating profit	649.3	701.7	1,267.3	1,397.1
U.S. Meals & Baking [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	1,317.0	1,371.7	2,335.8	2,463.2
U.S. Cereal [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	615.4	597.5	1,229.5	1,248.2
U.S. Snacks [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	560.5	484.2	1,097.1	1,003.3
Canada [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	257.6	242.6	496.9	457.2
U.S. Yogurt & Other [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	225.0	225.5	455.1	456.6
Pet [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	593.4	460.0	1,081.4	851.7
Operating profit	131.5	119.3	246.7	209.6
Convenience Stores & Foodservice [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	540.7	440.5	1,023.1	832.1
Operating profit	94.0	78.3	196.4	147.9
Europe & Australia [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	463.9	467.4	981.4	958.4
Operating profit	15.8	35.7	61.0	88.9
Asia & Latin America [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	450.5	430.0	863.6	812.7
Operating profit	$ 43.6	$ 30.4	$ 59.0	$ 50.5

The net result for the period of deducting operating expenses from operating revenues.

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