Investments , Marketable Securities, Credit Losses on and Maturities of Debt Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Apr. 24, 2015	Apr. 25, 2014	Apr. 26, 2013
Investment Holdings [Line Items]
Investments	$ 14,637	$ 12,838
Long-term Investments	706	821
Credit Loss Portion of Other-than-temporary Impairments on Debt Securities
Beginning Balance	4	9
Reductions for securities sold during the period	4	5
Ending Balance		4	$ 9
AFS Debt Maturities
Due in one year or less	1,812
Due after one year through five years	6,646
Due after five years through ten years	3,097
Due after ten years	182
Total debt securities	11,737
Investments
Investment Holdings [Line Items]
Available-for-sale securities, fair value	14,560	12,771
Trading securities, fair value	77	67
Investments Other than Available-for-sale and Trading Securities	0	0
Other Assets
Investment Holdings [Line Items]
Available-for-sale securities, fair value	186	155
Trading securities, fair value	0	0
Investments Other than Available-for-sale and Trading Securities	520	666
Debt Securities
AFS Gross Realized Gain (Loss)
Proceeds from sales	5,640	7,991	10,350
Gross realized gains	33	15	59
Gross realized losses	(19)	(12)	(17)
Impairment losses recognized	0	(1)	0
Equity Securities
AFS Gross Realized Gain (Loss)
Proceeds from sales	250	120	161
Gross realized gains	164	69	94
Gross realized losses	0	0	0
Impairment losses recognized	$ (29)	$ (9)	$ (21)