Investments (Additional Information) (Details) (USD $)	12 Months Ended			60 Months Ended
	Jul. 26, 2014	Jul. 27, 2013	Jul. 28, 2012	Jul. 26, 2014
Schedule of Investments [Line Items]
Marketable Securities, Realized Loss, Other than Temporary Impairments, Amount	$ 11,000,000	$ 0	$ 0
Other than temporary impairment, credit losses recognized in earnings, credit losses on debt securities held	0			0
Average daily balance of securities lending	1,500,000,000	700,000,000
Minimum market value percentage for collateral on loaned securities	102.00%
Secured lending transactions outstanding	0	0		0
Equity method investments, carrying value	630,000,000	591,000,000		630,000,000
VCE
Schedule of Investments [Line Items]
Cumulative gross investment in VCE	716,000,000			716,000,000
Equity Method Investment, Ownership Percentage	35.00%			35.00%
Investments for the period, equity method	185,000,000	93,000,000	276,000,000
Percentage Of Share In Gain Loss From Joint Ventures	36.80%
Losses from VCE	223,000,000	183,000,000	160,000,000	644,000,000
Equity method investments, carrying value	$ 72,000,000			$ 72,000,000