Fair Value of Financial Instruments (Details) (USD $) In Millions, unless otherwise specified	Apr. 30, 2014	Apr. 30, 2013
Assets:
Cash and cash equivalents	$ 437	$ 204
Derivative assets	7	5
Liabilities:
Derivative liabilities	7	4
Short-term debt	8	3
Short-term borrowings	8	3
Current portion of long-term debt	0	2
Current portion of long-term debt	0	2
Long-term Debt, Excluding Current Maturities	997	997
Long-term debt	963	1,011
Foreign Exchange Contract [Member]
Assets:
Currency derivatives, assets	7	5
Liabilities:
Currency derivatives, liabilities	7	4
Reported Value Measurement [Member]
Assets:
Cash and cash equivalents	437	204
Liabilities:
Short-term debt	8	3
Current portion of long-term debt	0	2
Long-term Debt, Excluding Current Maturities	997	997
Reported Value Measurement [Member] | Foreign Exchange Contract [Member]
Assets:
Currency derivatives, assets	7	5
Liabilities:
Currency derivatives, liabilities	$ 7	$ 4