Income Taxes - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			12 Months Ended			19 Months Ended
	Jul. 27, 2019	Jul. 28, 2018	Jan. 27, 2018	Jul. 27, 2019	Jul. 28, 2018	Jul. 29, 2017	Jul. 27, 2019
Income Tax [Line Items]
Tax Cuts and Jobs Act of 2017, provisional tax expense			$ 11,100		$ 10,400
Tax Cuts and Jobs Act, transition tax for accumulated foreign earnings, income tax benefit		$ (863)	$ 9,000		863
Tax Cuts and Jobs Act, reversal of previously reported benefit	$ 872
Tax Cuts and Jobs Act, transition tax expense (benefit)							$ 11,300
Tax Cuts and Jobs Act, tax expense for transition tax on accumulated foreign earnings							9,000
Tax Cuts and Jobs Act, tax expense for foreign withholding tax							1,200
Tax Cuts and Jobs Act, re-measurement of net deferred tax assets							1,100
Undistributed earnings of certain foreign subsidiaries on which tax is not provided	6,600			$ 6,600			6,600
Unrecognized deferred income tax liability	711			711			711
Gross income tax benefit attributable to tax incentives				$ 300	$ 900	$ 1,300
Gross income tax benefit attributable to tax incentives (in dollars per share)				$ 0.08	$ 0.19	$ 0.25
Unrecognized tax benefits that would affect the effective tax rate if realized	1,700			$ 1,700			1,700
Net interest expense, reduction related to unrecognized tax benefits				30	$ 10
Penalties, reduction related to unrecognized tax benefits				6
Reduction in net interest expense						$ 26
Reduction in penalties						4
Accrual for interest and penalties	220	$ 180		220	$ 180	$ 186	220
Unrecognized tax benefit that could be reduced in next 12 months	50			50			50
Foreign Tax Authority
Income Tax [Line Items]
Operating loss carryforwards	756			756			756
Valuation allowance	111			111			111
Tax credit carryforward	5			5			5
Federal
Income Tax [Line Items]
Operating loss carryforwards	676			676			676
Tax credit carryforward	25			25			25
State and Local Jurisdiction
Income Tax [Line Items]
Operating loss carryforwards	1,000			1,000			1,000
Tax credit carryforward	1,100			1,100			1,100
Valuation allowance	$ 346			$ 346			$ 346