Program Development Costs (Details) (USD $) In Millions, unless otherwise specified	May 31, 2014	May 31, 2013
Program Development Costs
Expected revenue from cargo loading system program	$ 300
Net costs capitalized associated with the engineering and development of the cargo system, current and noncurrent	139.8	130.9
Net costs capitalized associated with the engineering and development of the cargo system, current	27.6	6.0
Net costs capitalized associated with the engineering and development of the cargo system, non-current	$ 112.2	$ 124.9