Financial Instruments and Fair Value Measurements - Contractual Maturities of Debt Investments (Detail) $ in Millions	Jul. 26, 2019 USD ($)
Investments Debt And Equity Securities [Abstract]
Due in one year or less, Amortized Cost	$ 524
Due after one year through five years, Amortized Cost	146
Due after five years through ten years, Amortized Cost	5
Total, Amortized Cost	675
Due in one year or less, Estimated Fair Value	523
Due after one year through five years, Estimated Fair Value	146
Due after five years through ten years, Estimated Fair Value	5
Total, Estimated Fair Value	$ 674