Financial Instruments and Fair Value Measurements - Summary of Investments (Detail) - USD ($) $ in Millions	Jan. 27, 2017	Apr. 29, 2016
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	$ 2,684	$ 2,613
Gross unrealized gains	2	7
Gross unrealized losses	(6)	(1)
Estimated fair value	2,680	2,619
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	1,411	1,370
Gross unrealized gains	2	5
Gross unrealized losses	(3)	(1)
Estimated fair value	1,410	1,374
U.S. Treasury and Government Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	688	878
Gross unrealized gains	0	2
Gross unrealized losses	(3)	0
Estimated fair value	685	880
Foreign Government Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	27	35
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	27	35
Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	426	202
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	426	202
Certificates of Deposit
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	102	98
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	102	98
Mutual Funds
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	30	30
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	$ 30	$ 30