Earnings per Share (Schedule of earnings per share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Nov. 28, 2021	Nov. 29, 2020	Nov. 28, 2021	Nov. 29, 2020
Earnings Per Share [Abstract]
Net earnings attributable to General Mills	$ 597.2	$ 688.4	$ 1,224.2	$ 1,327.3
Average number of common shares - basic EPS	608.6	614.8	609.5	614.5
Earnings Per Share, Basic and Diluted [Abstract]
Average number of common shares - diluted EPS	613.0	619.6	613.8	619.7
Earnings per share - basic	$ 0.98	$ 1.12	$ 2.01	$ 2.16
Earnings per share - diluted	$ 0.97	$ 1.11	$ 1.99	$ 2.14
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental share effect	2.2	2.5	2.1	2.8
Restricted stock units and performance share units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental share effect	2.2	2.3	2.2	2.4