Financial Instruments and Fair Value Measurements - Summary of Investments (Detail) - USD ($) $ in Millions	Jan. 29, 2016	Apr. 24, 2015
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	$ 2,706	$ 3,681
Gross unrealized gains	3	11
Gross unrealized losses	(4)	0
Estimated fair value	2,705	3,692
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	1,496	2,249
Gross unrealized gains	2	9
Gross unrealized losses	(4)	0
Estimated fair value	1,494	2,258
U.S. Treasury and Government Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	1,019	1,056
Gross unrealized gains	1	2
Gross unrealized losses	0	0
Estimated fair value	1,020	1,058
Foreign Government Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	39	38
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	39	38
Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	7	20
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	7	20
Certificates of Deposit
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	116	286
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	116	286
Mutual Funds
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	29	32
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	$ 29	$ 32