Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Apr. 27, 2019 |
Apr. 28, 2018 |
Apr. 27, 2019 |
Apr. 28, 2018 |
|
| Disaggregation of Revenue [Line Items] | ||||
| Revenue | $ 12,958 | $ 12,463 | $ 38,476 | $ 36,486 |
| Product | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Revenue | 9,722 | 9,304 | 28,885 | 27,067 |
| Infrastructure Platforms | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Revenue | 7,545 | 7,180 | 22,315 | 20,870 |
| Applications | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Revenue | 1,431 | 1,310 | 4,315 | 3,697 |
| Security | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Revenue | 707 | 583 | 2,016 | 1,725 |
| Other Products | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Revenue | 39 | 231 | 239 | 775 |
| Other Products | Discontinued operations, held-for-sale | Service Provider Video | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Revenue | 0 | 219 | 168 | 697 |
| Service | ||||
| Disaggregation of Revenue [Line Items] | ||||
| Revenue | $ 3,236 | $ 3,159 | $ 9,591 | $ 9,419 |