Business Segment Information (Schedule of net sales by class of similar products) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	May 27, 2018	Feb. 25, 2018	Nov. 26, 2017	Aug. 27, 2017	May 28, 2017	Feb. 26, 2017	Nov. 27, 2016	Aug. 28, 2016	May 27, 2018	May 28, 2017	May 29, 2016
Product Information [Line Items]
Net sales	$ 3,890.2	$ 3,882.3	$ 4,198.7	$ 3,769.2	$ 3,806.6	$ 3,793.2	$ 4,112.1	$ 3,907.9	$ 15,740.4	$ 15,619.8	$ 16,563.1
Snacks [Member]
Product Information [Line Items]
Net sales									3,419.0	3,302.2	3,297.2
Cereal [Member]
Product Information [Line Items]
Net sales									2,679.2	2,673.2	2,731.5
Convenient meals [Member]
Product Information [Line Items]
Net sales									2,677.4	2,653.6	2,779.0
Yogurt [Member]
Product Information [Line Items]
Net sales									2,320.1	2,403.5	2,760.9
Dough [Member]
Product Information [Line Items]
Net sales									1,684.1	1,690.6	1,820.0
Baking mixes and ingredients [Member]
Product Information [Line Items]
Net sales									1,653.4	1,654.1	1,704.3
Super-premium ice cream [Member]
Product Information [Line Items]
Net sales									803.7	738.4	731.2
Vegetables [Member]
Product Information [Line Items]
Net sales									309.1	310.5	532.3
Other [Member]
Product Information [Line Items]
Net sales									$ 194.4	$ 193.7	$ 206.7