Business Segment and Geographic Information (Schedule of operating segment results) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Feb. 24, 2019	Feb. 25, 2018	Feb. 24, 2019	Feb. 25, 2018
Segment Reporting Information [Line Items]
Net sales	$ 4,198.3	$ 3,882.3	$ 12,703.5	$ 11,850.2
Divestiture loss	35.4	0.0	35.4	0.0
Operating profit	651.3	569.5	1,799.8	1,883.8
Restructuring, impairment, and other exit costs (recoveries)	59.7	7.5	267.7	14.3
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	4,198.3	3,882.3	12,703.5	11,850.2
Operating profit	795.2	627.8	2,342.2	2,064.9
Unallocated Corporate Items [Member]
Segment Reporting Information [Line Items]
Operating profit	48.8	50.8	239.3	166.8
Significant Reconciling Items [Member]
Segment Reporting Information [Line Items]
Restructuring, impairment, and other exit costs (recoveries)	59.7	7.5	267.7	14.3
North America Retail [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	2,518.6	2,517.4	7,583.5	7,727.4
Operating profit	581.6	518.3	1,749.5	1,674.4
U.S. Meals & Baking [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	1,027.8	1,010.6	3,039.9	3,063.3
U.S. Cereal [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	566.9	544.7	1,695.2	1,693.4
U.S. Snacks [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	497.6	504.2	1,535.4	1,587.7
U.S. Yogurt & Other [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	221.3	227.0	668.5	688.0
Canada [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	205.0	230.9	644.5	695.0
Convenience Stores & Foodservice [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	472.5	460.3	1,450.1	1,419.6
Operating profit	96.7	84.3	303.4	275.6
Europe & Australia [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	432.7	469.8	1,387.2	1,428.4
Operating profit	24.4	27.3	81.4	84.8
Asia & Latin America [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	427.7	434.8	1,257.4	1,274.8
Operating profit	19.5	(2.1)	49.6	30.1
Pet [Member] \| Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales	346.8	0.0	1,025.3	0.0
Operating profit	$ 73.0	$ 0.0	$ 158.3	$ 0.0

Amount of gain (loss) from sale and disposal of integrated set of activities and assets capable of being conducted and managed for purpose of providing return in form of dividend, lower cost, or other economic benefit to investor, owner, member and participant.

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Amount of restructuring charges, remediation cost, and asset impairment loss.

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