Derivative Financial Instruments (Details) (Currency derivatives [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Jul. 31, 2014	Jul. 31, 2013
Cash Flow Hedging [Member]
Derivative instrument gains and losses affecting statements of operations
Net gain (loss) recognized in AOCI	$ 5	$ 10
Net Sales [Member] | Cash Flow Hedging [Member]
Derivative instrument gains and losses affecting statements of operations
Net gain (loss) reclassified from AOCI into income	(2)	1
Net Sales [Member] | Not designated as hedges [Member]
Derivative instrument gains and losses affecting statements of operations
Gain (loss) on derivative instruments recognized in income	0	4
Other Income [Member] | Not designated as hedges [Member]
Derivative instrument gains and losses affecting statements of operations
Gain (loss) on derivative instruments recognized in income	$ (9)	$ 3