Derivative Instruments (Schedule of Notional Amounts of Derivatives Outstanding) (Details) - USD ($) |
Apr. 27, 2019 |
Jul. 28, 2018 |
|---|---|---|
| Derivative [Line Items] | ||
| Derivatives | $ 8,818,000,000 | $ 10,011,000,000 |
| Derivatives designated as hedging instruments: | Foreign currency derivatives | ||
| Derivative [Line Items] | ||
| Derivatives | 623,000,000 | 147,000,000 |
| Derivatives designated as hedging instruments: | Interest rate derivatives | ||
| Derivative [Line Items] | ||
| Derivatives | 4,500,000,000 | 6,750,000,000 |
| Derivatives designated as hedging instruments: | Net investment hedging instruments | ||
| Derivative [Line Items] | ||
| Derivatives | 363,000,000 | 250,000,000 |
| Derivatives not designated as hedging instruments: | Foreign currency derivatives | ||
| Derivative [Line Items] | ||
| Derivatives | 2,760,000,000 | 2,298,000,000 |
| Derivatives not designated as hedging instruments: | Total return swaps—deferred compensation | ||
| Derivative [Line Items] | ||
| Derivatives | $ 572,000,000 | $ 566,000,000 |