Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Millions	Jul. 28, 2019	Jan. 27, 2019
Assets
Cash equivalents and marketable securities	$ 8,372	$ 7,324
2.20% Notes Due 2021
Liabilities
Stated interest rate (as percent)	2.20%
3.20% Notes Due 2026
Liabilities
Stated interest rate (as percent)	3.20%
Corporate debt securities
Assets
Cash equivalents and marketable securities	$ 2,104	2,620
Debt securities of United States government agencies
Assets
Cash equivalents and marketable securities	1,120	2,280
Debt securities issued by the United States Treasury
Assets
Cash equivalents and marketable securities	2,161	1,492
Money market funds
Assets
Cash equivalents and marketable securities	2,868	483
Foreign government debt securities
Assets
Cash equivalents and marketable securities	45	209
Asset-backed securities
Assets
Cash equivalents and marketable securities	44	151
Certificates of deposit
Assets
Cash equivalents and marketable securities	24
Mortgage-backed securities issued by United States government-sponsored enterprises
Assets
Cash equivalents and marketable securities	6	89
Fair Value, Inputs, Level 1 | Money market funds
Assets
Cash equivalents and marketable securities		483
Fair Value, Inputs, Level 2 | 2.20% Notes Due 2021
Liabilities
Notes	999	978
Fair Value, Inputs, Level 2 | 3.20% Notes Due 2026
Liabilities
Notes	1,022	961
Fair Value, Inputs, Level 2 | Corporate debt securities
Assets
Cash equivalents and marketable securities		2,620
Fair Value, Inputs, Level 2 | Debt securities of United States government agencies
Assets
Cash equivalents and marketable securities		2,280
Fair Value, Inputs, Level 2 | Debt securities issued by the United States Treasury
Assets
Cash equivalents and marketable securities		1,492
Fair Value, Inputs, Level 2 | Foreign government debt securities
Assets
Cash equivalents and marketable securities		209
Fair Value, Inputs, Level 2 | Asset-backed securities
Assets
Cash equivalents and marketable securities		151
Fair Value, Inputs, Level 2 | Certificates of deposit
Assets
Cash equivalents and marketable securities	$ 24	0
Fair Value, Inputs, Level 2 | Mortgage-backed securities issued by United States government-sponsored enterprises
Assets
Cash equivalents and marketable securities		$ 89