Earnings Per Share (Schedule of earnings per share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ 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
Earnings Per Share [Abstract]
Net earnings attributable to General Mills	$ 416.8	$ 595.7	$ 688.4	$ 638.9	$ 625.7	$ 454.1	$ 580.8	$ 520.6	$ 2,339.8	$ 2,181.2	$ 1,752.7
Average number of common shares - basic EPS									614.1	608.1	600.4
Earnings Per Share, Basic and Diluted [Abstract]
Average number of common shares - diluted EPS									619.1	613.3	605.4
Earnings per share - basic	$ 0.68	$ 0.97	$ 1.12	$ 1.04	$ 1.03	$ 0.75	$ 0.96	$ 0.86	$ 3.81	$ 3.59	$ 2.92
Earnings per share - diluted	$ 0.68	$ 0.96	$ 1.11	$ 1.03	$ 1.02	$ 0.74	$ 0.95	$ 0.85	$ 3.78	$ 3.56	$ 2.90
Other Disclosures [Abstract]
Anti-dilutive stock options, restricted stock units, and performance share units									3.4	8.4	14.1
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental share effect									2.5	2.7	3.1
Restricted stock units and performance share units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental share effect									2.5	2.5	1.9