Derivatives and Currency Exchange Risk Management , Freestanding Derivative Contracts and Cash Flow Hedges (Details) - USD ($)	12 Months Ended
	Apr. 26, 2019	Apr. 27, 2018	Apr. 28, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gains (losses) relating to ineffectiveness of cash flow hedges	$ 0	$ 0	$ 0
Gains (losses) relating to ineffectiveness of forward starting interest rate derivative instruments			0
After-tax net unrealized gains (losses)	194,000,000	(207,000,000)
Cash flow hedge unrealized gains to be reclassified over the next twelve months, net of tax	175,000,000
Currency exchange rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gross notional amount	11,100,000,000	11,500,000,000
Currency exchange rate contracts | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Gross notional amount	4,300,000,000	5,200,000,000
Currency exchange rate contracts | Derivatives designated as hedging instruments | Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Gross notional amount	6,800,000,000	$ 6,300,000,000
Derivative term		2 years
Total return swaps | Derivatives not designated as hedging instruments
Derivative Instruments, Gain (Loss) [Line Items]
Gross notional amount	$ 191,000,000	$ 210,000,000
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Market value of derivative instruments - unrealized gains recorded in accumulated other comprehensive loss			21,000,000
Interest rate swaps | Derivatives designated as hedging instruments | Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, notional amount terminated			$ 300,000,000
Weighted average fixed rate of interest rate derivatives			3.10%