Financial Instruments - Notional Amounts and Credit Risk Amounts Associated with Derivative Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2017	Sep. 24, 2016
Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative [Line Items]
Derivative, notional amount	$ 56,156	$ 44,678
Derivative, credit risk amount	1,049	518
Derivatives designated as accounting hedges | Interest rate contracts
Derivative [Line Items]
Derivative, notional amount	33,000	24,500
Derivative, credit risk amount	218	728
Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative [Line Items]
Derivative, notional amount	69,774	54,305
Derivative, credit risk amount	$ 363	$ 153