Fair Value Measurements Fair Value Measurements Narrative (Details) - USD ($) $ in Millions	Apr. 26, 2020	Jul. 28, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	$ 15	$ 0
Cash and Cash Equivalents, at Carrying Value	15	0
Debt, Long-term and Short-term, Combined Amount	6,695	8,474
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, Long-term and Short-term, Combined Fair Value	7,216	8,642
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents, Fair Value Disclosure	0	19
Cash and Cash Equivalents, at Carrying Value	0	19
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt, Long-term and Short-term, Combined Fair Value	0	238
Cash and Cash Equivalents, at Carrying Value	$ 0	$ 238