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. 27, 2016	Nov. 29, 2015	Nov. 27, 2016	Nov. 29, 2015
Earnings Per Share [Abstract]
Net earnings attributable to General Mills		$ 481.8	$ 529.5	$ 890.8	$ 956.1
Average number of common shares - basic EPS		588.8	599.4	594.4	600.8
Earnings Per Share, Basic and Diluted [Abstract]
Average number of common shares - diluted EPS		599.7	612.4	606.0	614.1
Earnings per share - basic		$ 0.82	$ 0.88	$ 1.5	$ 1.59
Earnings per share - diluted		$ 0.8	$ 0.87	$ 1.47	$ 1.56
Other Disclosures [Abstract]
Anti-dilutive stock options, restricted stock units and performance share units		2.5	2.2	2.2	2.6
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental share effect	[1]	8.1	9.8	8.8	10.1
Restricted Stock, Restricted Stock Units, and Other [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Incremental share effect	[1]	2.8	3.2	2.8	3.2

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