Derivatives and Foreign Exchange Risk Management, Offsetting of Assets and Liabilities (Details) (USD $) In Millions, unless otherwise specified	Jul. 25, 2014	Apr. 25, 2014
Offsetting Assets and Liabilities [Line Items]
Derivative assets, gross amount	$ 176	$ 175
Gross amount not offset on the Balance Sheet, financial instruments	(61)	(95)
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	0	0
Derivative sssets, net amount	115	80
Derivative liabilities, gross amount	(68)	(127)
Gross amount not offset on the Balance Sheet, financial instruments	61	95
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	0	0
Derivative liabilities, net amount	(7)	(32)
Total derivatives, gross amount of recognized assets/(liabilities)	108	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	0	0
Total derivatives, net amount	108	48
Interest Rate Contracts
Offsetting Assets and Liabilities [Line Items]
Derivative assets, gross amount	80	86
Gross amount not offset on the Balance Sheet, financial instruments	(11)	(31)
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	0	0
Derivative sssets, net amount	69	55
Derivative liabilities, gross amount		(11)
Gross amount not offset on the Balance Sheet, financial instruments		11
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged		0
Derivative liabilities, net amount		0
Foreign Currency Exchange Rate Contracts
Offsetting Assets and Liabilities [Line Items]
Derivative assets, gross amount	96	89
Gross amount not offset on the Balance Sheet, financial instruments	(50)	(64)
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	0	0
Derivative sssets, net amount	46	25
Derivative liabilities, gross amount	(68)	(116)
Gross amount not offset on the Balance Sheet, financial instruments	61	84
Gross amount not offset on the Balance Sheet, cash collateral (received) or pledged	0	0
Derivative liabilities, net amount	$ (7)	$ (32)