Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Apr. 30, 2016	Apr. 30, 2015
Assets:
Cash and cash equivalents	$ 263	$ 370
Derivative assets	19	59
Liabilities:
Derivative liabilities	10	18
Short-term borrowings	271	190
Short-term borrowings	271	190
Current portion of long-term debt	0	250
Current portion of long-term debt	0	253
Long-term Debt, Excluding Current Maturities	1,230	743
Long-term debt	1,293	735
Foreign Exchange Contract [Member]
Assets:
Currency derivatives, assets	19	59
Liabilities:
Currency derivatives, liabilities	10	18
Reported Value Measurement [Member]
Assets:
Cash and cash equivalents	263	370
Liabilities:
Short-term borrowings	271	190
Current portion of long-term debt	0	250
Long-term Debt, Excluding Current Maturities	1,230	743
Reported Value Measurement [Member] | Foreign Exchange Contract [Member]
Assets:
Currency derivatives, assets	19	59
Liabilities:
Currency derivatives, liabilities	$ 10	$ 18