Derivatives and Currency Exchange Risk Management , Derivative Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	Apr. 26, 2019	Apr. 27, 2018
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 335	$ 79
Derivative liabilities	19	238
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	30	39
Derivative liabilities	$ 0	$ 20