Fair Value (Fair Value, Nonrecurring Measurement) (Details) - Fair Value, Measurements, Nonrecurring - Level 3 - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Apr. 27, 2019 |
Apr. 28, 2018 |
Apr. 27, 2019 |
Apr. 28, 2018 |
|
| Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items] | ||||
| Total gains (losses) for nonrecurring measurements | $ (3) | $ (18) | $ 3 | $ (37) |
| Non-marketable equity securities and equity method investments | ||||
| Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items] | ||||
| Total gains (losses) for nonrecurring measurements | (3) | (17) | 3 | (56) |
| Purchased intangible assets (impaired) | ||||
| Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items] | ||||
| Total gains (losses) for nonrecurring measurements | 0 | (1) | 0 | (1) |
| Property held for sale—land and buildings | ||||
| Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Line Items] | ||||
| Total gains (losses) for nonrecurring measurements | $ 0 | $ 0 | $ 0 | $ 20 |