Financial Instruments - Notional Amounts and Credit Risk Amounts Associated with Derivative Instruments (Details) - USD ($) $ in Millions	Dec. 26, 2020	Sep. 26, 2020
Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative [Line Items]
Derivatives, notional amount	$ 71,191	$ 57,410
Derivatives, credit risk amount	524	749
Derivatives designated as accounting hedges | Interest rate contracts
Derivative [Line Items]
Derivatives, notional amount	20,900	20,700
Derivatives, credit risk amount	1,443	1,557
Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative [Line Items]
Derivatives, notional amount	123,267	88,636
Derivatives, credit risk amount	$ 780	$ 303