Derivative Financial Instruments (Gain (Loss) on Derivatives Recognized in Consolidated Statement of Operations) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013
Cash Flow Hedging [Member] | Currency derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) recognized in AOCI	$ (7)	$ 7
Net Sales [Member] | Cash Flow Hedging [Member] | Currency derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) reclassified from AOCI into earnings	0	1
Net Sales [Member] | Not designated as hedges [Member] | Currency derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) recognized in earnings	1	0
Other Income [Member] | Not designated as hedges [Member] | Currency derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) recognized in earnings	10	(2)
Cost of Sales [Member] | Not designated as hedges [Member] | Commodity derivatives [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) recognized in earnings	0	4
Interest Expense [Member] | Fair Value Hedging [Member] | Interest Rate Swap [Member]
Fair values of derivative instruments affecting statements of operations
Net gain (loss) recognized in earnings	$ 0	$ 2