Derivatives and Currency Exchange Risk Management - Derivative Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Recurring - USD ($) $ in Millions	Oct. 26, 2018	Apr. 27, 2018
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	$ 294	$ 79
Derivative liabilities	41	238
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	27	39
Derivative liabilities	$ 29	$ 20