DISCONTINUED OPERATIONS AND OTHER DIVESTITURES - Private Brands Operations (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Feb. 26, 2017	Feb. 28, 2016	May 27, 2018	May 28, 2017	May 29, 2016	Feb. 01, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pre-tax charge to write-down goodwill and long-lived assets			$ 14.7	$ 343.3	$ 62.6
Loss on extinguishment of debt			0.0	93.3	23.9
Senior notes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on extinguishment of debt	$ 32.7	$ 23.9
Ralcorp
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate principal amount of senior notes repaid		$ 33.9			33.9
Loss on extinguishment of debt					5.4
Ralcorp | Senior notes | Senior notes due August 15, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate principal amount of senior notes repaid					$ 17.2
Stated interest rate (percent)					4.95%
Effective interest rate					2.83%
Ralcorp | Senior notes | Senior notes due August 15, 2039
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate principal amount of senior notes repaid					$ 16.7
Stated interest rate (percent)					6.625%
Effective interest rate					4.82%
Lamb Weston | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transition services income for performance of services			2.2	4.2
Private Brands | Disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash proceeds from disposition on a debt-free basis						$ 2,600.0
Transition services income for performance of services			$ 2.2	$ 16.9	$ 8.3
Private Brands | Held for sale, discontinued operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pre-tax charge to write-down goodwill and long-lived assets					1,920.0
After-tax charge to write-down goodwill and long-lived assets					$ 1,440.0