Retirement Plans (Details 3) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2015	Aug. 31, 2014
Pension Plans Contributions [Abstract]
Required U.S. pension plan contributions	$ 6	$ 82
Voluntary U.S. pension plan contributions	159	83
U.S. domestic pension contributions	165	$ 165
September 2015 U.S. Pension Plans contribution	$ 165