Financial Instruments and Fair Value Measurements - Contractual Maturities of Debt Investments (Detail) $ in Millions	Jan. 26, 2018 USD ($)
Investments Debt And Equity Securities [Abstract]
Due in one year or less, Amortized Cost	$ 1,215
Due after one year through five years, Amortized Cost	1,195
Due after five years through ten years, Amortized Cost	661
Total, Amortized Cost	3,071
Due in one year or less, Estimated Fair Value	1,215
Due after one year through five years, Estimated Fair Value	1,185
Due after five years through ten years, Estimated Fair Value	656
Total, Estimated Fair Value	$ 3,056