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Business Segment Information (Schedule of operating segment results) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	May 30, 2021	Feb. 28, 2021	Nov. 29, 2020	Aug. 30, 2020	May 31, 2020	Feb. 23, 2020	Nov. 24, 2019	Aug. 25, 2019	May 30, 2021	May 31, 2020	May 26, 2019
Segment Reporting Information [Line Items]
Net sales	$ 4,523.6	$ 4,520.0	$ 4,719.4	$ 4,364.0	$ 5,023.0	$ 4,180.3	$ 4,420.8	$ 4,002.5	$ 18,127.0	$ 17,626.6	$ 16,865.2
Operating profit									3,144.8	2,953.9	2,515.9
Divestitures loss									53.5	0.0	30.0
Restructuring, impairment, and other exit costs									170.4	24.4	275.1
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									18,127.0	17,626.6	16,865.2
Operating profit									3,580.8	3,487.4	3,160.8
Unallocated Corporate Items [Member]
Segment Reporting Information [Line Items]
Operating profit									212.1	509.1	339.8
Significant Reconciling Items [Member]
Segment Reporting Information [Line Items]
Divestitures loss									(53.5)	0.0	(30.0)
Restructuring, impairment, and other exit costs									170.4	24.4	275.1
North America Retail Segment [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									10,995.4	10,750.5	9,925.2
Operating profit									2,623.2	2,627.0	2,277.2
U.S. Meals & Baking [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									4,611.6	4,408.5	3,839.8
U.S. Cereal [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									2,455.2	2,434.1	2,255.4
U.S. Snacks [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									2,048.3	2,091.9	2,060.9
Canada [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									953.2	897.0	862.4
U.S. Yogurt & Other [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									927.1	919.0	906.7
Europe and Australia [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									1,981.5	1,838.9	1,886.7
Operating profit									151.0	113.8	123.3
Convenience Stores and Foodservice [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									1,742.4	1,816.4	1,969.1
Operating profit									306.0	337.2	419.5
Pet Segment [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									1,732.4	1,694.6	1,430.9
Operating profit									415.0	390.7	268.4
Asia and Latin America [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales									1,675.3	1,526.2	1,653.3
Operating profit									$ 85.6	$ 18.7	$ 72.4