Derivatives and Foreign Exchange Risk Management, Balance Sheet Presentation (Details) (USD $) In Millions, unless otherwise specified	Jan. 25, 2013	Apr. 27, 2012
Derivatives, Fair Value [Line Items]
Asset derivatives	$ 284	$ 254
Liability derivatives	162	82
Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset derivatives	283	254
Liability derivatives	162	80
Designated as Hedging Instrument | Foreign Currency Exchange Rate Contracts | Prepaid Expenses and Other Current Assets
Derivatives, Fair Value [Line Items]
Asset derivatives	75	74
Designated as Hedging Instrument | Foreign Currency Exchange Rate Contracts | Other Assets
Derivatives, Fair Value [Line Items]
Asset derivatives	40	13
Designated as Hedging Instrument | Foreign Currency Exchange Rate Contracts | Other Accrued Expenses
Derivatives, Fair Value [Line Items]
Liability derivatives	58	33
Designated as Hedging Instrument | Foreign Currency Exchange Rate Contracts | Other Long-term Liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives	30	2
Designated as Hedging Instrument | Interest Rate Contracts | Other Assets
Derivatives, Fair Value [Line Items]
Asset derivatives	168	167
Designated as Hedging Instrument | Interest Rate Contracts | Other Long-term Liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives	74	45
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Asset derivatives	1	0
Liability derivatives	0	2
Not Designated as Hedging Instrument | Foreign Currency Exchange Rate Contracts | Prepaid Expenses and Other Current Assets
Derivatives, Fair Value [Line Items]
Asset derivatives	1	0
Not Designated as Hedging Instrument | Foreign Currency Exchange Rate Contracts | Other Accrued Expenses
Derivatives, Fair Value [Line Items]
Liability derivatives	$ 0	$ 2