Derivative Instruments (Offsetting of Derivative Assets and Liabilities) (Details) - USD ($) $ in Millions	Jul. 28, 2018	Jul. 29, 2017
Derivatives assets
GROSS AMOUNTS OFFSET IN THE CONSOLIDATED BALANCE SHEET, Gross Amounts Recognized	$ 2	$ 149
GROSS AMOUNTS OFFSET IN THE CONSOLIDATED BALANCE SHEET, Gross Amounts Offset	0	0
GROSS AMOUNTS OFFSET IN THE CONSOLIDATED BALANCE SHEET, Net Amounts Presented	2	149
GROSS AMOUNTS NOT OFFSET IN THE CONSOLIDATED BALANCE SHEETBUT WITH LEGAL RIGHTS TO OFFSET, Gross Derivative Amounts	(2)	(4)
GROSS AMOUNTS NOT OFFSET IN THE CONSOLIDATED BALANCE SHEETBUT WITH LEGAL RIGHTS TO OFFSET, Cash Collateral	0	(81)
GROSS AMOUNTS NOT OFFSET IN THE CONSOLIDATED BALANCE SHEETBUT WITH LEGAL RIGHTS TO OFFSET, Net Amount	0	64
Derivatives liabilities
GROSS AMOUNTS OFFSET IN THE CONSOLIDATED BALANCE SHEET, Gross Amounts Recognized	74	4
GROSS AMOUNTS OFFSET IN THE CONSOLIDATED BALANCE SHEET, Gross Amounts Offset	0	0
GROSS AMOUNTS OFFSET IN THE CONSOLIDATED BALANCE SHEET, Net Amounts Presented	74	4
GROSS AMOUNTS NOT OFFSET IN THE CONSOLIDATED BALANCE SHEETBUT WITH LEGAL RIGHTS TO OFFSET, Gross Derivative Amounts	(2)	(4)
GROSS AMOUNTS NOT OFFSET IN THE CONSOLIDATED BALANCE SHEETBUT WITH LEGAL RIGHTS TO OFFSET, Cash Collateral	(53)	0
GROSS AMOUNTS NOT OFFSET IN THE CONSOLIDATED BALANCE SHEETBUT WITH LEGAL RIGHTS TO OFFSET, Net Amount	$ 19	$ 0

Fair value of liability associated with 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.

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