Derivative Financial Instruments (Textual) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative, Notional Amount	$ 1,152	$ 686
Net losses recorded in AOCI expected to reclassify to earnings during the next 12 months	4
Maximum term of outstanding derivative contracts (months)	27 months	24 months
Aggregate fair value of derivatives with creditworthiness requirements that were in a net liability position	$ 6	$ 2