Business Segment Information (Schedule of net sales by class of similar products) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	May 31, 2020	Feb. 23, 2020	Nov. 24, 2019	Aug. 25, 2019	May 26, 2019	Feb. 24, 2019	Nov. 25, 2018	Aug. 26, 2018	May 31, 2020	May 26, 2019	May 27, 2018
Product Information [Line Items]
Net sales	$ 5,023.0	$ 4,180.3	$ 4,420.8	$ 4,002.5	$ 4,161.7	$ 4,198.3	$ 4,411.2	$ 4,094.0	$ 17,626.6	$ 16,865.2	$ 15,740.4
Snacks [Member]
Product Information [Line Items]
Net sales									3,529.7	3,487.4	3,549.3
Cereal [Member]
Product Information [Line Items]
Net sales									2,874.1	2,672.8	2,679.8
Convenient meals [Member]
Product Information [Line Items]
Net sales									2,814.3	2,538.6	2,572.7
Yogurt [Member]
Product Information [Line Items]
Net sales									2,056.6	2,113.1	2,235.0
Dough [Member]
Product Information [Line Items]
Net sales									1,801.1	1,661.9	1,653.4
Pet [Member]
Product Information [Line Items]
Net sales									1,694.6	1,430.9	0.0
Baking mixes and ingredients [Member]
Product Information [Line Items]
Net sales									1,674.2	1,663.7	1,709.7
Super-premium ice cream [Member]
Product Information [Line Items]
Net sales									718.1	812.7	803.2
Vegetables and Other [Member]
Product Information [Line Items]
Net sales									$ 463.9	$ 484.1	$ 537.3