EMPLOYEE BENEFIT PLANS (Detail) - Schedule of recognized in accumulated other comprehensive loss (USD $) In Millions, unless otherwise specified	May 31, 2012	May 31, 2011
Net actuarial gain (loss)	$ (95.6)	$ (77.7)
Net prior service credit	0.8	1.5
Net amount recognized in Accumulated other comprehensive income (loss)	(94.8)	(76.2)
Pension Plans, Defined Benefit [Member]
Net actuarial gain (loss)	(76.4)	(56.4)
Net amount recognized in Accumulated other comprehensive income (loss)	(76.4)	(56.4)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Net actuarial gain (loss)	(19.2)	(21.3)
Net prior service credit	0.8	1.5
Net amount recognized in Accumulated other comprehensive income (loss)	$ (18.4)	$ (19.8)