Derivative Instruments (Offsetting of Derivative Assets and Liabilities) (Details) - USD ($) $ in Millions	Jul. 30, 2016	Jul. 25, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross Amount of Recognized Assets	$ 385	$ 218
Gross Amount Offset in Consolidated Balance Sheet	0	0
Net Amount Presented in Consolidated Balance Sheet	385	218
Gross Derivative Amount with Legal Right to Offset	(23)	(12)
Cash Collateral Received	(305)	(124)
Net Amount	57	82
Gross Amount of Recognized Liabilities	54	12
Gross Amount Offset in Consolidated Balance Sheet	0	0
Net Amount Presented on Consolidated Balance Sheet	54	12
Gross Derivative Amount with Legal Right to Offset	(23)	(12)
Cash Collateral Pledged	0	0
Net Amount	$ 31	$ 0