DISCONTINUED OPERATIONS, OTHER ASSETS HELD FOR SALE, AND THE FORMATION OF ARDENT MILLS (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Feb. 22, 2015	Feb. 23, 2014	Feb. 22, 2015	Feb. 23, 2014
Discontinued Operations and Disposal Groups [Abstract]
Net sales	$ 0	$ 459.2	$ 16.2	$ 1,443.6
Net gain on sale of businesses	0	0	627.3	32.1
Long-lived asset impairment charge	0	(25.4)	0	(25.4)
Income (loss) from operations of discontinued operations before income taxes and equity method investment earnings	0.3	38.6	(10.1)	94.0
Income before income taxes	0.3	13.2	617.2	100.7
Income tax expense	0.9	2.5	255.2	34.3
Equity method investment earnings	0	0.1	0	0.2
Income (loss) from discontinued operations, net of tax	$ (0.6)	$ 10.8	$ 362.0	$ 66.6

Disposal Group, Including Discontinued Operation, Impairment of Long-Lived Assets to be Disposed of

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Amount of share in income (loss) of the equity method investee after the disposal of the discontinued operation.

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Overall income (loss) from a disposal group that is classified as a component of the entity, before income tax, reported as a separate component of income before extraordinary items. Includes the following (before income tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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Amount, before tax, of loss recognized for the write-down to fair value, less cost to sell, of a disposal group. Includes before tax gain for a subsequent increase in fair value (less cost to sell) up to the cumulative loss previously recognized through write-downs.

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Tax effect allocated to a disposal group that is classified as a component of the entity reported as a separate component of income before extraordinary items. Includes the tax effects of the following: income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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Amount of operating income or loss attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.

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Amount of sales or other form of revenues attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.

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Amount of income (loss) from a disposal group, net of income tax before extraordinary items allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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