Marketable Securities - Unrealized Losses (Details) $ in Millions	Oct. 28, 2018 USD ($)
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	$ 3,004
Fair value, unrealized loss greater than 12 months	1,766
Fair value with unrealized loss, total	4,770
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	(1)
Unrealized loss, 12 months or greater, gross	(14)
Gross unrealized loss, total	(15)
Debt securities of United States government agencies
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	1,584
Fair value, unrealized loss greater than 12 months	507
Fair value with unrealized loss, total	2,091
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	(1)
Unrealized loss, 12 months or greater, gross	(4)
Gross unrealized loss, total	(5)
Debt securities issued by the United States Treasury
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	1,253
Fair value, unrealized loss greater than 12 months	289
Fair value with unrealized loss, total	1,542
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	0
Unrealized loss, 12 months or greater, gross	(2)
Gross unrealized loss, total	(2)
Corporate debt securities
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	167
Fair value, unrealized loss greater than 12 months	794
Fair value with unrealized loss, total	961
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	0
Unrealized loss, 12 months or greater, gross	(6)
Gross unrealized loss, total	(6)
Asset-backed securities
Fair value, unrealized loss position
Fair value, unrealized loss less than 12 months	0
Fair value, unrealized loss greater than 12 months	176
Fair value with unrealized loss, total	176
Unrealized Loss Position, Aggregate Losses
Unrealized loss, less than 12 months, gross	0
Unrealized loss, 12 months or greater, gross	(2)
Gross unrealized loss, total	$ (2)