Fair Value Measurements (Details 1) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Millions	May 30, 2010
Assets measured at fair value
Property, plant, and equipment	$ 35.0
Losses Recognized, Property, plant, and equipment	49.8
Noncurrent assets held for sale	30.4
Losses Recognized, Assets held for sale long lived	58.3
Losses Recognized Assets	108.1
Level 1 [Member]
Assets measured at fair value
Property, plant, and equipment	0
Noncurrent assets held for sale	0
Property, plant, and equipment and noncurrent assets, Total	0
Level 2 [Member]
Assets measured at fair value
Property, plant, and equipment	0
Noncurrent assets held for sale	0
Property, plant, and equipment and noncurrent assets, Total	0
Level 3 [Member]
Assets measured at fair value
Property, plant, and equipment	35.0
Noncurrent assets held for sale	30.4
Property, plant, and equipment and noncurrent assets, Total	$ 65.4

Losses Recognized Assets.

Name:	cag_LossesRecognizedAssets
Namespace Prefix:	cag
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Losses Recognized Assets Held For Sale Long Lived.

+ Details

Name:	cag_LossesRecognizedAssetsHeldForSaleLongLived
Namespace Prefix:	cag
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Losses Recognized Property plant and equipment.

+ Details

Name:	cag_LossesRecognizedPropertyPlantAndEquipment
Namespace Prefix:	cag
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ Details

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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

- Definition

Long-lived assets that are held for sale apart from normal operations and anticipated to be sold in less than one year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 157
-Paragraph 33
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Period Type:	instant

- Definition

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software, net of accumulated depreciation.

+ References

+ Details

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Period Type:	instant