DISCONTINUED OPERATIONS AND THE FORMATION OF ARDENT MILLS (Narrative) (Details) $ in Millions		3 Months Ended				9 Months Ended
	May. 29, 2014 USD ($)	Feb. 28, 2016 USD ($)	Feb. 22, 2015 USD ($)	Aug. 24, 2014 USD ($)	May. 25, 2014 USD ($) facility	Feb. 28, 2016 USD ($)	Feb. 22, 2015 USD ($)	Nov. 01, 2015 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset impairment charges						$ 8.4	$ 24.7
Loss on early retirement of debt		$ 23.9		$ 16.3		23.9	24.6
Income tax benefit		(20.9)	$ 97.2			445.6	(136.3)
Selling, general and administrative expenses		489.6	360.3			1,419.7	1,146.1
Ardent Mills
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash contribution	$ 49.0
Ownership interest (as percent)	44.00%
Proceeds from divestiture of business	$ 391.4
Income from operations of discontinued operations before income taxes							625.6
Income from discontinued operations, net of tax							375.9
Ardent Mills | Equity method investment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Selling, general and administrative expenses		2.6	3.5			8.4	10.8
Ardent Mills | Other assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Carrying value of equity method investment		717.7				717.7
Private Brands
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale price								$ 2,600.0
Asset impairment charges		22.5				1,920.0
After-tax asset impairment charges		22.1				1,440.0
Deferred tax asset		1,620.0				$ 1,620.0
Income tax benefit		20.7
Five small brands
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of goodwill			1,270.0
Impairment charges			$ 13.7
Various brands
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of goodwill							1,480.0
Impairment charges							$ 43.7
Three flour milling facilities
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of business					$ 163.0
Flour milling facilities sold | facility					3
Ralcorp
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Early repayment of senior debt		33.9
Loss on early retirement of debt		5.4
Senior notes | 2020 Maturity | Ralcorp
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Early repayment of senior debt		$ 17.2
Stated interest rate (as a percent)		4.95%				4.95%
Effective interest rate (as a percent)		2.83%				2.83%
Senior notes | 2039 Maturity | Ralcorp
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Early repayment of senior debt		$ 16.7
Stated interest rate (as a percent)		6.625%				6.625%
Effective interest rate (as a percent)		4.82%				4.82%