Environmental loss contingencies, number of sites under environmental matters for which acquired company has liability.

No definition available.

Name:	cag_EnvironmentalLossContingenciesNumberOfSitesUnderEnvironmentalMattersForWhichAcquiredCompanyHasLiability
Namespace Prefix:	cag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Lease, remaining lease terms.

+ References

No definition available.

+ Details

Name:	cag_LeaseRemainingLeaseTerms
Namespace Prefix:	cag_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Litigation settlement amount of guarantee.

+ References

No definition available.

+ Details

Name:	cag_LitigationSettlementAmountOfGuarantee
Namespace Prefix:	cag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Loss Contingency, Number of Additional Defendants

+ References

No definition available.

+ Details

Name:	cag_LossContingencyNumberOfAdditionalDefendants
Namespace Prefix:	cag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Loss contingency number of suits.

+ References

No definition available.

+ Details

Name:	cag_LossContingencyNumberOfSuits
Namespace Prefix:	cag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Loss Contingency, Settlement Agreement, Terms, Number of Installments.

+ References

No definition available.

+ Details

Name:	cag_LossContingencySettlementAgreementTermsNumberOfInstallments
Namespace Prefix:	cag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Optional Extension Periods For Sublease Agreement

+ References

No definition available.

+ Details

Name:	cag_NumberOfOptionalExtensionPeriodsForSubleaseAgreement
Namespace Prefix:	cag_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Proposed penalty for violation of air quality standards.

+ References

No definition available.

+ Details

Name:	cag_ProposedPenaltyForViolationOfAirQualityStandards
Namespace Prefix:	cag_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Threshold amount for environmental matters.

+ References

No definition available.

+ Details

Name:	cag_ThresholdAmountForEnvironmentalMatters
Namespace Prefix:	cag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total costs accrued as of the balance sheet date for environmental loss contingencies.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 25
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6395460&loc=d3e13647-108346

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859

+ Details

Name:	us-gaap_AccrualForEnvironmentalLossContingencies
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_GuaranteeObligationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=124440162&loc=d3e12069-110248

+ Details

Name:	us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918673-209980

+ Details

Name:	us-gaap_LesseeOperatingLeaseRenewalTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount awarded to other party in judgment or settlement of litigation.

+ References

No definition available.

+ Details

Name:	us-gaap_LitigationSettlementAmountAwardedToOtherParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of litigation expense, including but not limited to legal, forensic, accounting, and investigative fees.

+ References

No definition available.

+ Details

Name:	us-gaap_LitigationSettlementExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of loss contingency liability.

+ References

+ Details

Name:	us-gaap_LossContingencyAccrualAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14435-108349

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14557-108349

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124440162&loc=d3e12021-110248

+ Details

Name:	us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=cag_LambWestonHoldingsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=cag_BeatriceMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=cag_OtherAccruedLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherNoncurrentLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=cag_PerformanceAndPaymentGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_GuaranteeObligationsByNatureAxis=us-gaap_PropertyLeaseGuaranteeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=stpr_IL
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=stpr_CA
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=cag_NegreteVConAgraFoodsCaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

CONTINGENCIES - Narrative (Details)				9 Months Ended	12 Months Ended
CONTINGENCIES - Narrative (Details)	Feb. 18, 2022 USD ($)	Jul. 24, 2019 USD ($) Installment	Jan. 27, 2014 USD ($) defendant	Feb. 27, 2022 USD ($) suit site period	May 30, 2021 USD ($)	May 31, 2020 USD ($)	Sep. 04, 2018 USD ($)
Guarantee Obligations [Line Items]
Threshold amount for environmental matters				$ 1,000,000.0
Proposed penalty for violation of air quality standards					$ 4,300,000	$ 1,800,000
Lamb Weston
Guarantee Obligations [Line Items]
Number of optional extension periods \| period				1
Period of optional extensions				5 years
Beatrice
Guarantee Obligations [Line Items]
Number of sites under environmental matters for which acquired company has a liability \| site				40
Accrual for environmental matters				$ 51,900,000
Beatrice \| Other accrued liabilities
Guarantee Obligations [Line Items]
Accrual for environmental matters				2,400,000
Beatrice \| Other noncurrent liabilities
Guarantee Obligations [Line Items]
Accrual for environmental matters				49,500,000
Performance and payment guarantee for Lamb Weston
Guarantee Obligations [Line Items]
Guarantee under sublease agreement (maximum)				75,000,000.0
Performance and payment of all amounts under sublease agreement
Guarantee Obligations [Line Items]
Guarantee under sublease agreement (maximum)				$ 11,900,000
Remaining lease terms				5 years
Illinois
Guarantee Obligations [Line Items]
Remaining defendants in active suits \| suit				1
California \| Negrete v. ConAgra Foods Case
Guarantee Obligations [Line Items]
Settlement require to pay	$ 9,400,000
California \| Beatrice
Guarantee Obligations [Line Items]
Number of other defendants \| defendant			2
Estimate of possible loss			$ 1,150,000,000				$ 409,000,000.0
Total payments to be made under settlement		$ 101,700,000,000
Number of annual installments to be made \| Installment		7
California \| Beatrice \| Maximum
Guarantee Obligations [Line Items]
Litigation settlement, amount of guarantee provided				$ 15,000,000.0
California \| Beatrice \| Minimum \| Other accrued liabilities
Guarantee Obligations [Line Items]
Amount accrued				11,400,000
California \| Beatrice \| Minimum \| Other noncurrent liabilities
Guarantee Obligations [Line Items]
Amount accrued				$ 40,600,000