Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Millions	Oct. 27, 2019	Jan. 27, 2019
Assets
Cash equivalents and marketable securities	$ 9,657	$ 7,324
2.20% Notes Due 2021
Liabilities
Stated interest rate	2.20%
3.20% Notes Due 2026
Liabilities
Stated interest rate	3.20%
Debt securities issued by the United States Treasury
Assets
Cash equivalents and marketable securities	$ 5,883	1,492
Corporate debt securities
Assets
Cash equivalents and marketable securities	1,293	2,620
Debt securities of United States government agencies
Assets
Cash equivalents and marketable securities	1,204	2,280
Money market funds
Assets
Cash equivalents and marketable securities	1,070	483
Foreign government debt securities
Assets
Cash equivalents and marketable securities	178	209
Certificates of deposit
Assets
Cash equivalents and marketable securities	25
Asset-backed securities
Assets
Cash equivalents and marketable securities	4	151
Mortgage-backed securities issued by United States government-sponsored enterprises
Assets
Cash equivalents and marketable securities		89
Fair Value, Inputs, Level 1 | Money market funds
Assets
Cash equivalents and marketable securities	1,070	483
Fair Value, Inputs, Level 2 | 2.20% Notes Due 2021
Liabilities
Notes	1,003	978
Fair Value, Inputs, Level 2 | 3.20% Notes Due 2026
Liabilities
Notes	1,051	961
Fair Value, Inputs, Level 2 | Debt securities issued by the United States Treasury
Assets
Cash equivalents and marketable securities	5,883	1,492
Fair Value, Inputs, Level 2 | Corporate debt securities
Assets
Cash equivalents and marketable securities	1,293	2,620
Fair Value, Inputs, Level 2 | Debt securities of United States government agencies
Assets
Cash equivalents and marketable securities	1,204	2,280
Fair Value, Inputs, Level 2 | Foreign government debt securities
Assets
Cash equivalents and marketable securities	178	209
Fair Value, Inputs, Level 2 | Certificates of deposit
Assets
Cash equivalents and marketable securities	25	0
Fair Value, Inputs, Level 2 | Asset-backed securities
Assets
Cash equivalents and marketable securities	4	151
Fair Value, Inputs, Level 2 | Mortgage-backed securities issued by United States government-sponsored enterprises
Assets
Cash equivalents and marketable securities	$ 0	$ 89