Financial Instruments and Fair Value Measurements - Contractual Maturities of Debt Investments (Detail) $ in Millions	Jan. 27, 2017 USD ($)
Investments Debt And Equity Securities [Abstract]
Due in one year or less, Amortized Cost	$ 1,281
Due after one year through five years, Amortized Cost	1,363
Due after five years through ten years, Amortized Cost	5
Due after ten years, Amortized Cost	5
Total, Amortized Cost	2,654
Due in one year or less, Estimated Fair Value	1,281
Due after one year through five years, Estimated Fair Value	1,359
Due after five years through ten years, Estimated Fair Value	5
Due after ten years, Estimated Fair Value	5
Total, Estimated Fair Value	$ 2,650