INCOME TAXES (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2012	Nov. 30, 2011	May 31, 2012
Income Taxes [Abstract]
Effective income tax rate	21.30%	25.90%	22.90%	25.80%
Net deferred tax assets	$ 1,600		$ 1,600		$ 1,400