DERIVATIVE FINANCIAL INSTRUMENTS (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Feb. 28, 2016	Feb. 22, 2015	Feb. 24, 2013	Feb. 28, 2016	Feb. 22, 2015	May. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Hedge for anticipated consumption of commodity inputs, period (up to)				36 months
Deferred gain (loss) on derivative	$ 0.0	$ 0.0		$ 0.0	$ 0.0
Unamortized amounts of deferred gain (loss)	(329.0)			(329.0)		$ (329.5)
Derivative asset prior to offsetting to total derivative	11.1			11.1		7.3
Derivative liability prior to offsetting to total derivative	14.1			14.1		13.2
Maximum amount of loss due to the credit risk of the counterparties	24.4			24.4
Open commodity purchase contracts
Derivative Instruments, Gain (Loss) [Line Items]
Notional value of open commodity contracts	177.9			177.9		554.9
Open commodity sales contracts
Derivative Instruments, Gain (Loss) [Line Items]
Notional value of open commodity contracts	108.7			108.7		393.1
Prepaid expenses and other current assets
Derivative Instruments, Gain (Loss) [Line Items]
Amounts representing a right to reclaim cash collateral	3.0			3.0		5.9
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Net gain	0.5			1.7
Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Notional value of open commodity contracts	116.9			116.9		$ 108.6
Cash flow hedging | 2043 Maturity
Derivative Instruments, Gain (Loss) [Line Items]
Deferred gain (loss) on derivative			$ 4.2
Cash flow hedging | 2043 Maturity | Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Unamortized amounts of deferred gain (loss)	0.7			0.7
Cash flow hedging | 2023 Maturity
Derivative Instruments, Gain (Loss) [Line Items]
Deferred gain (loss) on derivative			$ (2.0)
Cash flow hedging | 2023 Maturity | Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Unamortized amounts of deferred gain (loss)	(1.0)			(1.0)
Fair value hedging
Derivative Instruments, Gain (Loss) [Line Items]
Loss on change of fair value of senior long-term debt		5.7			5.8
Fair value hedging | Selling, general and administrative expense
Derivative Instruments, Gain (Loss) [Line Items]
Net gain		2.5			3.1
Fair value hedging | Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain on change in fair value of interest rate swap contracts		$ 8.2			$ 8.9
Cumulative adjustment to fair value of hedged debt instruments	12.6			12.6
Unamortized amount of deferred gain on debt instruments hedged	$ 7.0			$ 7.0