Investments (Additional Information) (Details)	12 Months Ended
	Jul. 29, 2017 USD ($) entity	Jul. 30, 2016 USD ($)	Jul. 25, 2015 USD ($)
Investments, Debt and Equity Securities [Abstract]
Impairment charges of available-for-sale investments	$ 74,000,000	$ 3,000,000	$ 0
Other than temporary impairment, credit losses recognized in earnings, credit losses on debt securities held	0
Average daily balance of securities lending	$ 700,000,000	600,000,000
Minimum market value percentage for collateral on loaned securities (at least)	102.00%
Secured lending transactions outstanding	$ 0	0
Number of variable interest entities required to be consolidated (entity) | entity	0
Variable Interest Entity [Line Items]
Investments in privately held companies	$ 983,000,000	$ 1,003,000,000
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Investments in privately held companies	553,000,000
Funding commitments	$ 216,000,000