Name:	gis_ReclassificationToRetainedEarningsRelatedToAdoptionOfAccountingStandardsUpdate201802
Namespace Prefix:	gis_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Blended U.S federal statutory tax rate resulting from the 35% tax rate prior to the enactment of the U.S. Tax Cuts and Jobs Act of 2017 and the 21% tax rate post enactment.

No definition available.

Name:	gis_TaxCutsAndJobsActOf2017BlendedTaxRate
Namespace Prefix:	gis_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Net amount of provisional deferred income tax expense (benefit) resulting from revaluing the net U.S. deferred tax liabilities to reflect the new U.S. corporate tax rate as a result of the U.S. Tax Cuts and Jobs Act of 2017.

No definition available.

Name:	gis_TaxCutsAndJobsActOf2017ProvisionalDeferredIncomeTaxExpenseBenefitNet
Namespace Prefix:	gis_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Net amount of provisional deferred income tax expense (benefit) related to changes in the indefinite reinvestment assertion as a result of the U.S. Tax Cuts and Jobs Act of 2017.

No definition available.

Name:	gis_TaxCutsAndJobsActOf2017ProvisionalDeferredIncomeTaxExpenseBenefitNetChangeInIndefiniteReinvestmentAssertion
Namespace Prefix:	gis_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Net amount of discrete provisional income tax expense (benefit) pertaining to continuing operations recognized as a result of the U.S. Tax Cuts and Jobs Act of 2017.

No definition available.

Name:	gis_TaxCutsAndJobsActOf2017ProvisionalIncomeTaxExpenseBenefitNet
Namespace Prefix:	gis_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Net amount of provisional transition tax expense (benefit) recognized as a result of the U.S. Tax Cuts and Jobs Act of 2017.

No definition available.

Name:	gis_TaxCutsAndJobsActOf2017ProvisionalTransitionTaxExpenseBenefitNet
Namespace Prefix:	gis_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Transition tax rate on accumulated foreign earnings and profits pertaining to liquid assets as a result of the deemed repatriation imposed by the U.S. Tax Cuts and Jobs Act of 2017.

No definition available.

Name:	gis_TaxCutsAndJobsActOf2017TransitionTaxPercentageOnAccumulatedForeignEarningsAndProfitsApplicableToLiquidAssets
Namespace Prefix:	gis_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Transition tax rate on accumulated foreign earnings and profits pertaining to unremitted foreign earnings and profits as a result of the deemed repatriation imposed by the U.S. Tax Cuts and Jobs Act of 2017.

No definition available.

Name:	gis_TaxCutsAndJobsActOf2017TransitionTaxPercentageOnAccumulatedForeignEarningsAndProfitsApplicableToUnremittedForeignEarningsAndProfits
Namespace Prefix:	gis_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

Name:	us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.