Investments (Maturities Of Fixed Income Securities) (Details) (USD $) In Millions, unless otherwise specified	Apr. 25, 2015
Schedule of Investments [Line Items]
Amortized Cost	$ 48,472
Fair Value	48,626
Less than 1 year
Schedule of Investments [Line Items]
Amortized Cost	16,322
Fair Value	16,332
Due in 1 to 2 years
Schedule of Investments [Line Items]
Amortized Cost	14,969
Fair Value	15,006
Due in 2 to 5 years
Schedule of Investments [Line Items]
Amortized Cost	15,610
Fair Value	15,697
Due after 5 years
Schedule of Investments [Line Items]
Amortized Cost	1,571
Fair Value	$ 1,591