Derivatives and Currency Exchange Risk Management - Offsetting Assets and Liabilities (Details) - USD ($) $ in Millions	Jan. 24, 2020	Apr. 26, 2019
Derivative assets:
Gross Amount of Recorded Assets (Liabilities)	$ 284	$ 365
Gross Amount Not Offset on the Balance Sheet, Financial Instruments	(33)	(9)
Gross Amount Not Offset on the Balance Sheet, Cash Collateral Posted (Received)	(5)	(44)
Net Amount	246	312
Derivative liabilities:
Gross Amount of Recorded Assets (Liabilities)	(33)	(19)
Gross Amount Not Offset on the Balance Sheet, Financial Instruments	33	9
Gross Amount Not Offset on the Balance Sheet, Cash Collateral Posted (Received)	0	0
Net Amount	0	(10)
Total
Gross Amount of Recorded Assets (Liabilities)	251	346
Gross Amount Not Offset on the Balance Sheet, Financial Instruments	0	0
Gross Amount Not Offset on the Balance Sheet, Cash Collateral Posted (Received)	(5)	(44)
Net Amount	246	302
Currency exchange rate contracts
Derivative assets:
Gross Amount of Recorded Assets (Liabilities)	267	335
Gross Amount Not Offset on the Balance Sheet, Financial Instruments	(33)	(9)
Gross Amount Not Offset on the Balance Sheet, Cash Collateral Posted (Received)	(5)	(43)
Net Amount	229	283
Derivative liabilities:
Gross Amount of Recorded Assets (Liabilities)	(33)	(19)
Gross Amount Not Offset on the Balance Sheet, Financial Instruments	33	9
Gross Amount Not Offset on the Balance Sheet, Cash Collateral Posted (Received)	0	0
Net Amount	0	(10)
Interest rate contracts
Derivative assets:
Gross Amount of Recorded Assets (Liabilities)		9
Gross Amount Not Offset on the Balance Sheet, Financial Instruments		0
Gross Amount Not Offset on the Balance Sheet, Cash Collateral Posted (Received)		(1)
Net Amount		8
Total return swaps
Derivative assets:
Gross Amount of Recorded Assets (Liabilities)	16	15
Gross Amount Not Offset on the Balance Sheet, Financial Instruments	0	0
Gross Amount Not Offset on the Balance Sheet, Cash Collateral Posted (Received)	0	0
Net Amount	16	15
Cross currency interest rate contracts
Derivative assets:
Gross Amount of Recorded Assets (Liabilities)	1	6
Gross Amount Not Offset on the Balance Sheet, Financial Instruments	0	0
Gross Amount Not Offset on the Balance Sheet, Cash Collateral Posted (Received)	0	0
Net Amount	$ 1	$ 6

Derivative Asset (Liability) [Abstract]

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Derivative Asset (Liability), Fair Value, Gross Asset (Liability)

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Derivative Assets and Liabilities, Net, Collateral, Obligation to Return Cash

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Derivative Assets and Liabilities, Net, Not Offset, Policy Election Deduction

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Fair value of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be offset, deducted from derivative assets.

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Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets.

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Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities.

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The net amount as of the balance sheet date of the fair value of derivative assets and derivative liabilities that in accordance with the entity's accounting policy were offset against collateral under a master netting arrangement.

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, after effects of master netting arrangements, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset offset against an obligation to return collateral. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value, after effects of master netting arrangements, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset offset against the right to receive collateral. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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