Debt and Credit Facilities (Tables)

12 Months Ended

Apr. 30, 2016

Debt Disclosure [Abstract]

Schedule of long-term debt

Our long-term debt (net of unamortized discounts and issuance costs) consisted of:

April 30,	2015		2016
2.50% senior notes, $250 principal amount, due in fiscal 2016	$	250	$	—
1.00% senior notes, $250 principal amount, due in fiscal 2018	248		249
2.25% senior notes, $250 principal amount, due in fiscal 2023	247		248
3.75% senior notes, $250 principal amount, due in fiscal 2043	248		248
4.50% senior notes, $500 principal amount, due in fiscal 2046	—		485
	993		1,230
Less current portion	250		—
	$	743	$	1,230