Marketable Securities (Details) - USD ($) $ in Millions	Oct. 29, 2017	Jan. 29, 2017
Summary of cash equivalents and marketable securities:
Amortized Cost	$ 6,140	$ 5,484
Unrealized Gain	2	3
Unrealized Loss	(15)	(19)
Classified as:
Cash equivalents	2,609	436
Marketable securities	3,518	5,032
Total cash equivalents and marketable securities	6,127	5,468
Amortized Cost
Less than one year	4,074	2,209
Due in 1-5 years	2,024	3,210
Mortgage-backed securities issued by government-sponsored enterprises not due to a single maturity date	42	65
Total	6,140	5,484
Estimated Fair Value
Less than one year	4,072	2,209
Due in 1-5 years	2,013	3,194
Mortgage-backed securities issued by United States government-sponsored enterprises not due to a single maturity date	42	65
Total	6,127	5,468
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	2,301
Fair value, unrealized loss greater than 12 months	849
Fair value with unrealized loss, total	3,150
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	(9)
Unrealized loss, 12 months or greater, gross	(6)
Gross unrealized loss, total	(15)
Corporate debt securities
Summary of cash equivalents and marketable securities:
Amortized Cost	1,515	2,397
Unrealized Gain	0	1
Unrealized Loss	(5)	(10)
Classified as:
Cash equivalents	0	33
Marketable securities	1,510	2,355
Total cash equivalents and marketable securities	1,510	2,388
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	867
Fair value, unrealized loss greater than 12 months	407
Fair value with unrealized loss, total	1,274
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	(3)
Unrealized loss, 12 months or greater, gross	(2)
Gross unrealized loss, total	(5)
Debt securities of United States government agencies
Summary of cash equivalents and marketable securities:
Amortized Cost	907	1,193
Unrealized Gain	0	0
Unrealized Loss	(5)	(5)
Classified as:
Cash equivalents	0	27
Marketable securities	902	1,161
Total cash equivalents and marketable securities	902	1,188
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	666
Fair value, unrealized loss greater than 12 months	236
Fair value with unrealized loss, total	902
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	(3)
Unrealized loss, 12 months or greater, gross	(2)
Gross unrealized loss, total	(5)
Debt securities issued by the United States Treasury
Summary of cash equivalents and marketable securities:
Amortized Cost	638	852
Unrealized Gain	0	0
Unrealized Loss	(3)	(2)
Classified as:
Cash equivalents	0	55
Marketable securities	635	795
Total cash equivalents and marketable securities	635	850
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	509
Fair value, unrealized loss greater than 12 months	126
Fair value with unrealized loss, total	635
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	(2)
Unrealized loss, 12 months or greater, gross	(1)
Gross unrealized loss, total	(3)
Asset-backed Securities
Summary of cash equivalents and marketable securities:
Amortized Cost	289	490
Unrealized Gain	0	0
Unrealized Loss	(1)	(1)
Classified as:
Cash equivalents	0	0
Marketable securities	288	489
Total cash equivalents and marketable securities	288	489
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	233
Fair value, unrealized loss greater than 12 months	44
Fair value with unrealized loss, total	277
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	(1)
Unrealized loss, 12 months or greater, gross	0
Gross unrealized loss, total	(1)
Mortgage backed securities issued by United States government-sponsored enterprises
Summary of cash equivalents and marketable securities:
Amortized Cost	140	161
Unrealized Gain	2	2
Unrealized Loss	(1)	(1)
Classified as:
Cash equivalents	0	0
Marketable securities	141	162
Total cash equivalents and marketable securities	141	162
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	26
Fair value, unrealized loss greater than 12 months	36
Fair value with unrealized loss, total	62
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	0
Unrealized loss, 12 months or greater, gross	(1)
Gross unrealized loss, total	(1)
Foreign government bonds
Summary of cash equivalents and marketable securities:
Amortized Cost	42	70
Unrealized Gain	0	0
Unrealized Loss	0	0
Classified as:
Cash equivalents	0	0
Marketable securities	42	70
Total cash equivalents and marketable securities	42	70
Money market funds
Summary of cash equivalents and marketable securities:
Amortized Cost	2,609	321
Unrealized Gain	0	0
Unrealized Loss	0	0
Classified as:
Cash equivalents	2,609	321
Marketable securities	0	0
Total cash equivalents and marketable securities	$ 2,609	$ 321