Debt (Tables)

6 Months Ended

Oct. 31, 2016

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments

Our long-term debt (net of unamortized discount and issuance costs) consists of:

(Principal and carrying amounts in millions)	April 30, 2016		October 31, 2016
1.00% notes, $250 principal amount, due January 15, 2018	$	249	$	249
2.25% notes, $250 principal amount, due January 15, 2023	248		248
1.20% notes, €300 principal amount, due July 7, 2026	—		326
2.60% notes, £300 principal amount, due July 7, 2028	—		360
3.75% notes, $250 principal amount, due January 15, 2043	248		248
4.50% notes, $500 principal amount, due July 15, 2045	485		486
	$	1,230	$	1,917