Financial Instruments and Fair Value Measurements - Summary of Investments (Detail) - USD ($) $ in Millions	Oct. 30, 2015	Apr. 24, 2015
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	$ 2,772	$ 3,681
Gross unrealized gains	4	11
Gross unrealized losses	(3)	0
Estimated fair value	2,773	3,692
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	1,614	2,249
Gross unrealized gains	3	9
Gross unrealized losses	(2)	0
Estimated fair value	1,615	2,258
U.S. Treasury and Government Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	927	1,056
Gross unrealized gains	1	2
Gross unrealized losses	(1)	0
Estimated fair value	927	1,058
Foreign Government Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	44	38
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	44	38
Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	44	20
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	44	20
Certificates of Deposit
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	109	286
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	109	286
Mutual Funds
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	34	32
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	$ 34	$ 32