Investments, Marketable Securities, Credit Losses on and Maturities of Debt Securities (Details) (USD $) In Millions, unless otherwise specified	Jan. 24, 2014	Apr. 26, 2013
Long-term
Investments	$ 12,363	$ 10,211
Long-term investments	867	843
Credit Loss Portion of Other-than-temporary Impairments on Debt Securities
Ending Balance	4	9
AFS Debt Maturities
Due in one year or less	1,510
Due after one year through five years	6,802
Due after five years through ten years	2,798
Due after ten years	128
Total debt securities	11,238
Investments [Member]
Long-term
Available-for-sale securities, fair value	12,298	10,161
Trading securities, fair value	65	50
Investments Other than Available-for-sale and Trading Securities	0	0
Other Assets
Long-term
Available-for-sale securities, fair value	197	294
Trading securities, fair value	0	0
Investments Other than Available-for-sale and Trading Securities	$ 670	$ 549