Acquired finite lived intangible assets amount.

Name:	cag_AcquiredFiniteLivedIntangibleAssetsAmount
Namespace Prefix:	cag
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Business acquisition costs of acquired entity cash paid.

+ Details

Name:	cag_BusinessAcquisitionCostsOfAcquiredEntityCashPaid
Namespace Prefix:	cag
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Business acquisitions purchase price allocation goodwill amount.

+ Details

Name:	cag_BusinessAcquisitionsPurchasePriceAllocationGoodwillAmount
Namespace Prefix:	cag
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Business acquisitions purchase price allocation goodwill amount and finite lived intangible assets amount.

+ Details

Name:	cag_BusinessAcquisitionsPurchasePriceAllocationGoodwillAmountAndFiniteLivedIntangibleAssetsAmount
Namespace Prefix:	cag
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Distribution of initial investment by acquiree.

+ Details

Name:	cag_DistributionOfInitialInvestmentByAcquiree
Namespace Prefix:	cag
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=6970148&loc=SL6759159-111685

+ Details

Name:	us-gaap_VariableInterestEntityOwnershipPercentage
Namespace Prefix:	us-gaap
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Acquisitions (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	May 29, 2011	May 30, 2010 Elan Nutrition, Inc [Member]	May 30, 2010 Elan Nutrition, Inc [Member]	Aug. 31, 2010 American Pie LIC [Member]	May 29, 2011 American Pie LIC [Member]	Nov. 23, 2008 Lamb Weston BSW [Member]	May 31, 2009 Lamb Weston BSW [Member]	May 31, 2009 Individually Immaterial Acquisitions [Member]
Business Acquisition [Line Items]
Cash paid to acquire the entity		$ 103.5		$ 131.0		$ 46.2		$ 18.4
Purchase price allocated to goodwill		66.4	66.4	51.5		18.8	18.8
Purchase price allocated to brands, trademarks and other intangibles	18.0	33.6		61.3	61.3	11.1
Purchase price allocated to goodwill, brands, trademarks and other intangibles								15.1
Percentage of interest acquired						49.99%
Distribution of initial investment by acquiree						$ 20.0