ACQUISITIONS (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended					12 Months Ended
	May. 31, 2015	Jul. 31, 2014	Sep. 30, 2013	Jan. 31, 2013	Aug. 31, 2012	May. 31, 2015	May. 25, 2014	May. 26, 2013
Business Acquisitions [Line Items]
Purchase price allocated to goodwill	$ 6,300.3					$ 6,300.3	$ 7,828.5	$ 8,418.7
Consideration paid for the merger						95.7	39.9	5,018.8
Conagra Foods
Business Acquisitions [Line Items]
Business acquisition transaction related expenses				$ 71.4
Business acquisition non recurring expense				16.7
Ralcorp
Business Acquisitions [Line Items]
Business acquisition transaction related expenses				84.4
Private Brands
Business Acquisitions [Line Items]
Purchase price allocated to goodwill	1,669.5					1,669.5	3,214.6	3,793.2
Consumer Foods
Business Acquisitions [Line Items]
Purchase price allocated to goodwill	3,743.1					3,743.1	3,748.5	3,760.5
Commercial Foods
Business Acquisitions [Line Items]
Purchase price allocated to goodwill	887.7					887.7	$ 865.4	$ 865.0
Blake's All Natural Foods
Business Acquisitions [Line Items]
Payments to acquire a business	20.7
Purchase price allocated to goodwill	$ 20.0					$ 20.0
TaiMei Potato Industry Limited
Business Acquisitions [Line Items]
Payments to acquire a business		$ 92.2
Purchase price allocated to goodwill		23.8
Consideration paid for the merger		74.9
Brands, trademarks and other intangibles		$ 3.3
Harlan Bakeries
Business Acquisitions [Line Items]
Payments to acquire a business			$ 39.9
Ralcorp
Business Acquisitions [Line Items]
Purchase price allocated to goodwill				4,380.0
Consideration paid for the merger				4,750.0
Brands, trademarks and other intangibles				2,170.0
Purchase price allocated to brands, trademarks and other intangibles				2,030.0
Intangibles				134.1
Deductible for tax purposes				397.0
Ralcorp | Private Brands
Business Acquisitions [Line Items]
Purchase price allocated to goodwill				3,520.0
Ralcorp | Consumer Foods
Business Acquisitions [Line Items]
Purchase price allocated to goodwill				512.0
Ralcorp | Commercial Foods
Business Acquisitions [Line Items]
Purchase price allocated to goodwill				$ 350.6
P F Changs And Bertolli Brands Frozen Meal Business
Business Acquisitions [Line Items]
Payments to acquire a business					$ 266.9
Purchase price allocated to goodwill					100.1
Brands, trademarks and other intangibles					$ 91.8