Business Segment and Geographic Information (Schedule of net sales by class of similar products) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 27, 2022	Feb. 28, 2021	Feb. 27, 2022	Feb. 28, 2021
Product Information [Line Items]
Net sales	$ 4,537.7	$ 4,520.0	$ 14,101.6	$ 13,603.4
Snacks [Member]
Product Information [Line Items]
Net sales	925.3	871.9	2,827.4	2,608.6
Convenient meals [Member]
Product Information [Line Items]
Net sales	772.8	785.0	2,258.1	2,334.8
Cereal [Member]
Product Information [Line Items]
Net sales	754.4	715.4	2,227.6	2,168.7
Pet [Member]
Product Information [Line Items]
Net sales	568.1	436.3	1,649.5	1,288.0
Dough [Member]
Product Information [Line Items]
Net sales	446.6	498.0	1,458.8	1,456.8
Baking mixes and ingredients [Member]
Product Information [Line Items]
Net sales	465.9	416.8	1,379.4	1,293.6
Yogurt [Member]
Product Information [Line Items]
Net sales	349.3	505.3	1,362.3	1,513.5
Super-premium ice cream [Member]
Product Information [Line Items]
Net sales	151.4	164.0	596.2	596.4
Other [Member]
Product Information [Line Items]
Net sales	$ 103.9	$ 127.3	$ 342.3	$ 343.0