Financial Instruments and Fair Value Measurements - Summary of Investments (Detail) - USD ($) $ in Millions	Jan. 25, 2019	Apr. 27, 2018
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	$ 1,955	$ 2,738
Gross unrealized gains	0	1
Gross unrealized losses	(36)	(44)
Estimated fair value	1,919	2,695
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	1,523	1,865
Gross unrealized gains	0	1
Gross unrealized losses	(34)	(39)
Estimated fair value	1,489	1,827
U.S. Treasury and Government Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	283	497
Gross unrealized gains	0	0
Gross unrealized losses	(2)	(5)
Estimated fair value	281	492
Commercial Paper
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	0	230
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	0	230
Certificates of Deposit
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	117	115
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	117	115
Mutual Funds
Schedule of Available-for-sale Securities [Line Items]
Cost or amortized cost	32	31
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Estimated fair value	$ 32	$ 31

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

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