DOCUMENT AND ENTITY INFORMATION - USD ($) $ in Millions	12 Months Ended
	May 31, 2020	Jun. 15, 2020	Nov. 24, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Entity Central Index Key	0000040704
Document Annual Report	true
Document Period End Date	May 31, 2020
Document Transition Report	false
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020
Current Fiscal Year End Date	--05-31
Entity File Number	001-01185
Entity Registrant Name	GENERAL MILLS, INC.
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	41-0274440
Entity Address Address Line 1	Number One General Mills Boulevard
Entity Address City or Town	Minneapolis
Entity Address State or Province	MN
Entity Address Postal Zip Code	55426
City Area Code	(763)
Local Phone Number	764-7600
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Voluntary Filers	No
Entity Well Known Seasoned Issuer	Yes
Entity Public Float			$ 31,856.1
Entity Common Stock, Shares Outstanding		609,869,264
Entity Listings [Line Items]
Documents Incorporated By Reference	Portions of the registrant’s Proxy Statement for its 2020 Annual Meeting of Shareholders are incorporated by reference into Part III.
Common Stock, $.10 par value [Member]
Entity Listings [Line Items]
Security 12b Title	Common Stock, $.10 par value
Trading Symbol	GIS
Security Exchange Name	NYSE
2.100% Notes due 2020 [Member]
Entity Listings [Line Items]
Security 12b Title	2.100% Notes due 2020
Trading Symbol	GIS20
Security Exchange Name	NYSE
1.000% Notes due 2023 [Member]
Entity Listings [Line Items]
Security 12b Title	1.000% Notes due 2023
Trading Symbol	GIS23A
Security Exchange Name	NYSE
0.450% Notes due 2026 [Member]
Entity Listings [Line Items]
Security 12b Title	0.450% Notes due 2026
Trading Symbol	GIS26
Security Exchange Name	NYSE
1.500% Notes due 2027 [Member]
Entity Listings [Line Items]
Security 12b Title	1.500% Notes due 2027
Trading Symbol	GIS27
Security Exchange Name	NYSE