Business Acquisition, Equity Interest Issued or Issuable, Par Value of Shares

No definition available.

Name:	cag_BusinessAcquisitionEquityInterestIssuedOrIssuableParValueOfShares
Namespace Prefix:	cag_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Proceeds from issuance of common stock, net of stock issuance costs.

+ References

No definition available.

+ Details

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

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

+ Details

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

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

- Definition

Number of new stock issued during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of treasury shares or units reissued. Excludes reissuance of shares or units in treasury for award under share-based payment arrangement.

+ References

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=cag_UnderwrittenPublicOfferingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=cag_PinnacleFoodsIncPinnacleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

EARNINGS PER SHARE - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended	12 Months Ended
	Oct. 26, 2018	Nov. 25, 2018	May 31, 2020	May 26, 2019	May 27, 2018
Stock options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Stock options outstanding excluded from EPS calculation (in shares)			1.9	2.0	1.3
Underwritten Public Offering
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Issuance of common stock (in shares)		16.3
Common stock, par value (in dollars per share)		$ 5.00
Issuance of Conagra Brands, Inc. common shares, net		$ 555.7
Pinnacle Foods Inc. (Pinnacle)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Company shares issued out of treasury (shares)	77.5	77.5
Issuance of Conagra Brands, Inc. common shares, net	$ 555.7