Financial Instruments - Notional Amounts and Credit Risk Amounts Associated with Derivative Instruments (Details) - USD ($) $ in Millions	Dec. 28, 2019	Sep. 28, 2019
Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative [Line Items]
Derivative, notional amount	$ 54,215	$ 61,795
Derivative, credit risk amount	1,625	1,798
Derivatives designated as accounting hedges | Interest rate contracts
Derivative [Line Items]
Derivative, notional amount	28,250	31,250
Derivative, credit risk amount	475	685
Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative [Line Items]
Derivative, notional amount	96,470	76,868
Derivative, credit risk amount	$ 327	$ 323