Financial Instruments - Notional Amounts and Credit Risk Amounts Associated with Derivative Instruments (Details) - USD ($) $ in Millions	Dec. 29, 2018	Sep. 29, 2018
Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative [Line Items]
Derivative, notional amount	$ 56,000	$ 65,368
Derivative, credit risk amount	1,110	1,015
Derivatives designated as accounting hedges | Interest rate contracts
Derivative [Line Items]
Derivative, notional amount	33,250	33,250
Derivative, credit risk amount	22	0
Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative [Line Items]
Derivative, notional amount	82,013	63,062
Derivative, credit risk amount	$ 419	$ 259