Derivative Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Cash Flow Hedging [Member] | Currency derivatives [Member]
Derivative instrument gains and losses affecting statements of operations
Net gain (loss) recognized in AOCI	$ (15)	$ (14)	$ (5)	$ (1)
Net Sales [Member] | Cash Flow Hedging [Member] | Currency derivatives [Member]
Derivative instrument gains and losses affecting statements of operations
Net gain (loss) reclassified from AOCI into income			1	1
Net Sales [Member] | Not designated as hedges [Member] | Currency derivatives [Member]
Derivative instrument gains and losses affecting statements of operations
Gain (loss) on derivative instruments recognized in income	(5)	(1)	(1)	(1)
Interest Expense [Member] | Fair Value Hedging [Member] | Interest rate swaps [Member]
Derivative instrument gains and losses affecting statements of operations
Gain (loss) on derivative instruments recognized in income			0	1
Other Income [Member] | Not designated as hedges [Member] | Currency derivatives [Member]
Derivative instrument gains and losses affecting statements of operations
Gain (loss) on derivative instruments recognized in income	0	2	2	(2)
Cost of Sales [Member] | Not designated as hedges [Member] | Commodity derivatives [Member]
Derivative instrument gains and losses affecting statements of operations
Gain (loss) on derivative instruments recognized in income			$ 0	$ 4