Investments (Maturities Of Fixed Income Securities) (Details) (USD $) In Millions, unless otherwise specified	Jul. 26, 2014
Schedule of Investments [Line Items]
Amortized Cost	$ 43,305
Fair Value	43,396
Less than 1 year
Schedule of Investments [Line Items]
Amortized Cost	15,444
Fair Value	15,457
Due in 1 to 2 years
Schedule of Investments [Line Items]
Amortized Cost	13,449
Fair Value	13,484
Due in 2 to 5 years
Schedule of Investments [Line Items]
Amortized Cost	13,711
Fair Value	13,743
Due after 5 years
Schedule of Investments [Line Items]
Amortized Cost	701
Fair Value	$ 712