Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash Reported in the Consolidated Balance Sheet that sum to the Total Amount in the Statement of Cash Flow (Details) - USD ($) $ in Millions	Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017	Oct. 01, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 5,418	$ 4,150	$ 4,017
Restricted Cash and Investments, Current	26	1	26
Restricted Cash and Investments, Noncurrent	11	4	21
Cash, cash equivalents and restricted cash	$ 5,455	$ 4,155	$ 4,064	$ 4,760