Derivatives and Foreign Exchange Risk Management, Offsetting Assets and Liabilities (Details) (USD $) In Millions, unless otherwise specified	Jan. 23, 2015	Apr. 25, 2014
Offsetting Assets and Liabilities [Line Items]
Derivative assets, gross amount	$ 578	$ 175
Gross amount not offset on the Balance Sheet, financial instruments	(77)	(95)
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	(304)	0
Derivative sssets, net amount	197	80
Derivative liabilities, gross amount	(105)	(127)
Gross amount not offset on the Balance Sheet, financial instruments	77	95
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	0	0
Derivative liabilities, net amount	(28)	(32)
Total derivatives, gross amount of recognized assets/(liabilities)	473	48
Total gross amount not offset on the Balance Sheet, financial instruments	0	0
Total gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	(304)	0
Total derivatives, net amount	169	48
Foreign Currency Exchange Rate Contracts
Offsetting Assets and Liabilities [Line Items]
Derivative assets, gross amount	482	89
Gross amount not offset on the Balance Sheet, financial instruments	(61)	(64)
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	(292)	0
Derivative sssets, net amount	129	25
Derivative liabilities, gross amount	(32)	(116)
Gross amount not offset on the Balance Sheet, financial instruments	32	84
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	0	0
Derivative liabilities, net amount	0	(32)
Interest Rate Contracts
Offsetting Assets and Liabilities [Line Items]
Derivative assets, gross amount	96	86
Gross amount not offset on the Balance Sheet, financial instruments	(16)	(31)
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	(12)	0
Derivative sssets, net amount	68	55
Derivative liabilities, gross amount	(73)	(11)
Gross amount not offset on the Balance Sheet, financial instruments	45	11
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	0	0
Derivative liabilities, net amount	$ (28)	$ 0