Acquired Intangible Assets - Additional Information (Detail) - USD ($) $ in Billions |
12 Months Ended | ||
|---|---|---|---|
Sep. 24, 2016 |
Sep. 26, 2015 |
Sep. 27, 2014 |
|
| Goodwill and Intangible Assets Disclosure [Abstract] | |||
| Amortization expense related to acquired intangible assets | $ 1.5 | $ 1.3 | $ 1.1 |
| Weighted-average amortization period for acquired intangible assets (in years) | 3 years 4 months 24 days | ||