Marketable Securities (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jul. 29, 2018	Jul. 30, 2017	Jul. 29, 2018	Jul. 30, 2017	Jan. 28, 2018
Summary of cash equivalents and marketable securities:
Unrealized Gain	$ 3,000,000		$ 3,000,000		$ 2,000,000
Unrealized Loss	(19,000,000)		(19,000,000)		(23,000,000)
Reported as
Cash Equivalents	483,000,000		483,000,000		3,789,000,000
Marketable Securities	7,225,000,000		7,225,000,000		3,106,000,000
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	2,053,000,000		2,053,000,000
Fair value, unrealized loss greater than 12 months	1,928,000,000		1,928,000,000
Fair value with unrealized loss, total	3,981,000,000		3,981,000,000
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	(3,000,000)		(3,000,000)
Unrealized loss, 12 months or greater, gross	(16,000,000)		(16,000,000)
Gross unrealized loss, total	(19,000,000)		(19,000,000)
Other-than-temporary impairment losses	0	$ 0	0	$ 0
Amortized Cost
Less than 1 year	5,991,000,000		5,991,000,000		5,381,000,000
Due in 1 - 5 years	1,705,000,000		1,705,000,000		1,500,000,000
Mortgage-backed securities issued by United States government-sponsored enterprises not due at a single maturity date	28,000,000		28,000,000		35,000,000
Amortized Cost	7,724,000,000		7,724,000,000		6,916,000,000
Estimated Fair Value
Less than 1 year	5,981,000,000		5,981,000,000		5,375,000,000
Due in 1 - 5 years	1,699,000,000		1,699,000,000		1,485,000,000
Mortgage-backed securities issued by United States government-sponsored enterprises not due at a single maturity date	28,000,000		28,000,000		35,000,000
Estimated Fair Value	7,708,000,000		7,708,000,000		6,895,000,000
Corporate debt securities
Summary of cash equivalents and marketable securities:
Unrealized Gain	1,000,000		1,000,000		0
Unrealized Loss	(8,000,000)		(8,000,000)		(9,000,000)
Reported as
Cash Equivalents	0		0		0
Marketable Securities	2,484,000,000		2,484,000,000		1,295,000,000
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	310,000,000		310,000,000
Fair value, unrealized loss greater than 12 months	742,000,000		742,000,000
Fair value with unrealized loss, total	1,052,000,000		1,052,000,000
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	(1,000,000)		(1,000,000)
Unrealized loss, 12 months or greater, gross	(7,000,000)		(7,000,000)
Gross unrealized loss, total	(8,000,000)		(8,000,000)
Amortized Cost
Amortized Cost	2,491,000,000		2,491,000,000		1,304,000,000
Estimated Fair Value
Estimated Fair Value	2,484,000,000		2,484,000,000		1,295,000,000
Debt securities issued by the United States Treasury
Summary of cash equivalents and marketable securities:
Unrealized Gain	0		0		0
Unrealized Loss	(2,000,000)		(2,000,000)		(4,000,000)
Reported as
Cash Equivalents	0		0		0
Marketable Securities	2,410,000,000		2,410,000,000		573,000,000
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	754,000,000		754,000,000
Fair value, unrealized loss greater than 12 months	410,000,000		410,000,000
Fair value with unrealized loss, total	1,164,000,000		1,164,000,000
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	0		0
Unrealized loss, 12 months or greater, gross	(2,000,000)		(2,000,000)
Gross unrealized loss, total	(2,000,000)		(2,000,000)
Amortized Cost
Amortized Cost	2,412,000,000		2,412,000,000		577,000,000
Estimated Fair Value
Estimated Fair Value	2,410,000,000		2,410,000,000		573,000,000
Debt securities of United States government agencies
Summary of cash equivalents and marketable securities:
Unrealized Gain	0		0		0
Unrealized Loss	(6,000,000)		(6,000,000)		(7,000,000)
Reported as
Cash Equivalents	0		0		0
Marketable Securities	1,987,000,000		1,987,000,000		815,000,000
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	925,000,000		925,000,000
Fair value, unrealized loss greater than 12 months	559,000,000		559,000,000
Fair value with unrealized loss, total	1,484,000,000		1,484,000,000
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	(1,000,000)		(1,000,000)
Unrealized loss, 12 months or greater, gross	(5,000,000)		(5,000,000)
Gross unrealized loss, total	(6,000,000)		(6,000,000)
Amortized Cost
Amortized Cost	1,993,000,000		1,993,000,000		822,000,000
Estimated Fair Value
Estimated Fair Value	1,987,000,000		1,987,000,000		815,000,000
Money market funds
Summary of cash equivalents and marketable securities:
Unrealized Gain	0		0		0
Unrealized Loss	0		0		0
Reported as
Cash Equivalents	483,000,000		483,000,000		3,789,000,000
Marketable Securities	0		0		0
Amortized Cost
Amortized Cost	483,000,000		483,000,000		3,789,000,000
Estimated Fair Value
Estimated Fair Value	483,000,000		483,000,000		3,789,000,000
Asset-backed securities
Summary of cash equivalents and marketable securities:
Unrealized Gain	0		0		0
Unrealized Loss	(2,000,000)		(2,000,000)		(2,000,000)
Reported as
Cash Equivalents	0		0		0
Marketable Securities	204,000,000		204,000,000		252,000,000
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	49,000,000		49,000,000
Fair value, unrealized loss greater than 12 months	155,000,000		155,000,000
Fair value with unrealized loss, total	204,000,000		204,000,000
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	(1,000,000)		(1,000,000)
Unrealized loss, 12 months or greater, gross	(1,000,000)		(1,000,000)
Gross unrealized loss, total	(2,000,000)		(2,000,000)
Amortized Cost
Amortized Cost	206,000,000		206,000,000		254,000,000
Estimated Fair Value
Estimated Fair Value	204,000,000		204,000,000		252,000,000
Mortgage-backed securities issued by United States government-sponsored enterprises
Summary of cash equivalents and marketable securities:
Unrealized Gain	2,000,000		2,000,000		2,000,000
Unrealized Loss	(1,000,000)		(1,000,000)		0
Reported as
Cash Equivalents	0		0		0
Marketable Securities	108,000,000		108,000,000		130,000,000
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	15,000,000		15,000,000
Fair value, unrealized loss greater than 12 months	31,000,000		31,000,000
Fair value with unrealized loss, total	46,000,000		46,000,000
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	0		0
Unrealized loss, 12 months or greater, gross	(1,000,000)		(1,000,000)
Gross unrealized loss, total	(1,000,000)		(1,000,000)
Amortized Cost
Amortized Cost	107,000,000		107,000,000		128,000,000
Estimated Fair Value
Estimated Fair Value	108,000,000		108,000,000		130,000,000
Foreign government bonds
Summary of cash equivalents and marketable securities:
Unrealized Gain	0		0		0
Unrealized Loss	0		0		(1,000,000)
Reported as
Cash Equivalents	0		0		0
Marketable Securities	32,000,000		32,000,000		41,000,000
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	0		0
Fair value, unrealized loss greater than 12 months	31,000,000		31,000,000
Fair value with unrealized loss, total	31,000,000		31,000,000
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	0		0
Unrealized loss, 12 months or greater, gross	0		0
Gross unrealized loss, total	0		0
Amortized Cost
Amortized Cost	32,000,000		32,000,000		42,000,000
Estimated Fair Value
Estimated Fair Value	$ 32,000,000		$ 32,000,000		$ 41,000,000