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. 24, 2019		Feb. 25, 2018		Feb. 24, 2019	Feb. 25, 2018
Earnings Per Share [Abstract]
Net earnings attributable to General Mills	$ 446.8		$ 941.4		$ 1,182.5	$ 1,776.6
Average number of common shares - basic EPS	600.4		572.5		599.3	573.4
Earnings Per Share, Basic and Diluted [Abstract]
Average number of common shares - diluted EPS	604.5		582.7		604.0	583.2
Earnings per share - basic	$ 0.74		$ 1.64		$ 1.97	$ 3.1
Earnings per share - diluted	$ 0.74		$ 1.62		$ 1.96	$ 3.05
Other Disclosures [Abstract]
Anti-dilutive stock options, restricted stock units and performance share units	14.4		5.2		14.1	6.8
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental share effect	2.2	[1]	7.9	[1]	3.0	7.7
Restricted Stock, Restricted Stock Units, and Other [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental share effect	1.9	[1]	2.3	[1]	1.7	2.1

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