DISCONTINUED OPERATIONS AND THE FORMATION OF ARDENT MILLS (Assets and Liabilities Classified as Held for Sale) (Details) - USD ($) $ in Millions	Feb. 28, 2016	May. 31, 2015	Feb. 22, 2015	May. 25, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	$ 0.0	$ 18.4	$ 27.5	$ 64.9
Current assets held for sale	4.2	744.3
Noncurrent assets held for sale	0.0	4,246.9
Current liabilities held for sale	0.0	294.0
Noncurrent liabilities held for sale	0.6	711.0
Discontinued operations, held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	0.0	18.4
Receivables, less allowance for doubtful accounts of $0.0 and $0.5	0.0	199.3
Inventories	4.2	489.3
Prepaid expenses and other current assets	0.0	37.3
Current assets held for sale	4.2	744.3
Property, plant and equipment, net	0.0	920.4
Goodwill	0.0	1,600.8
Brands, trademarks and other intangibles, net	0.0	1,716.6
Other assets	0.0	9.1
Noncurrent assets held for sale	0.0	4,246.9
Accounts payable	0.0	219.5
Accrued payroll	0.0	7.1
Other accrued liabilities	0.0	67.4
Current liabilities held for sale	0.0	294.0
Other noncurrent liabilities	0.6	711.0
Noncurrent liabilities held for sale	$ 0.6	$ 711.0