Earnings per Share (Schedule of earnings per share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Feb. 23, 2020	Feb. 24, 2019	Feb. 23, 2020	Feb. 24, 2019
Earnings Per Share [Abstract]
Net earnings attributable to General Mills		$ 454.1	$ 446.8	$ 1,555.5	$ 1,182.5
Average number of common shares - basic EPS		607.9	600.4	607.1	599.3
Earnings Per Share, Basic and Diluted [Abstract]
Average number of common shares - diluted EPS		612.8	604.5	612.1	604.0
Earnings per share - basic		$ 0.75	$ 0.74	$ 2.56	$ 1.97
Earnings per share - diluted		$ 0.74	$ 0.74	$ 2.54	$ 1.96
Other Disclosures [Abstract]
Anti-dilutive stock options, restricted stock units and performance share units		10.5	14.4	10.4	14.1
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental share effect	[1]	2.6	2.2	2.8	3.0
Restricted Stock, Restricted Stock Units, and Other [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental share effect	[1]	2.3	1.9	2.2	1.7

[1] Incremental shares from stock options, restricted stock units, and performance share units are computed by the treasury stock method.