DISCONTINUED OPERATIONS AND THE FORMATION OF ARDENT MILLS (Assets and Liabilities Classified as Held for Sale) (Additional Information) (Details) - USD ($) $ in Millions	Aug. 30, 2015	May. 31, 2015
Discontinued Operations and Disposal Groups [Abstract]
Allowance for doubtful accounts	$ 0.4	$ 0.5

Disposal Group, Including Discontinued Operation, Allowance for Doubtful Accounts Receivable

No definition available.

Name:	cag_DisposalGroupIncludingDiscontinuedOperationAllowanceforDoubtfulAccountsReceivable
Namespace Prefix:	cag_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant