Marketable Securities (Details) - USD ($) $ in Millions	Oct. 28, 2018	Jan. 28, 2018
Summary of cash equivalents and marketable securities:
Amortized Cost	$ 7,485	$ 6,916
Unrealized Gain	2	2
Unrealized Loss	(15)	(23)
Estimated Fair Value	7,472	6,895
Reported as
Cash Equivalents	602	3,789
Marketable Securities	6,870	3,106
Money market funds
Summary of cash equivalents and marketable securities:
Amortized Cost	602	3,789
Unrealized Gain	0	0
Unrealized Loss	0	0
Estimated Fair Value	602	3,789
Reported as
Cash Equivalents	602	3,789
Marketable Securities	0	0
Corporate debt securities
Summary of cash equivalents and marketable securities:
Amortized Cost	2,732	1,304
Unrealized Gain	1	0
Unrealized Loss	(6)	(9)
Estimated Fair Value	2,727	1,295
Reported as
Cash Equivalents	0	0
Marketable Securities	2,727	1,295
Debt securities of United States government agencies
Summary of cash equivalents and marketable securities:
Amortized Cost	2,140	822
Unrealized Gain	0	0
Unrealized Loss	(5)	(7)
Estimated Fair Value	2,135	815
Reported as
Cash Equivalents	0	0
Marketable Securities	2,135	815
Debt securities issued by the United States Treasury
Summary of cash equivalents and marketable securities:
Amortized Cost	1,544	577
Unrealized Gain	0	0
Unrealized Loss	(2)	(4)
Estimated Fair Value	1,542	573
Reported as
Cash Equivalents	0	0
Marketable Securities	1,542	573
Asset-backed securities
Summary of cash equivalents and marketable securities:
Amortized Cost	178	254
Unrealized Gain	0	0
Unrealized Loss	(2)	(2)
Estimated Fair Value	176	252
Reported as
Cash Equivalents	0	0
Marketable Securities	176	252
Mortgage-backed securities issued by United States government-sponsored enterprises
Summary of cash equivalents and marketable securities:
Amortized Cost	98	128
Unrealized Gain	1	2
Unrealized Loss	0	0
Estimated Fair Value	99	130
Reported as
Cash Equivalents	0	0
Marketable Securities	99	130
Foreign government bonds
Summary of cash equivalents and marketable securities:
Amortized Cost	191	42
Unrealized Gain	0	0
Unrealized Loss	0	(1)
Estimated Fair Value	191	41
Reported as
Cash Equivalents	0	0
Marketable Securities	$ 191	$ 41