Financial Instruments - Derivative Instruments at Gross Fair Value (Details) - Level 2 - USD ($) $ in Millions	Jun. 26, 2021	Sep. 26, 2020
Other current assets and other non-current assets | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	$ 1,210	$ 1,052
Other current assets and other non-current assets | Interest rate contracts
Derivative assets:
Fair value of derivative assets	891	1,557
Other current assets and other non-current assets | Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	700	749
Other current assets and other non-current assets | Derivatives designated as accounting hedges | Interest rate contracts
Derivative assets:
Fair value of derivative assets	891	1,557
Other current assets and other non-current assets | Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	510	303
Other current assets and other non-current assets | Derivatives not designated as accounting hedges | Interest rate contracts
Derivative assets:
Fair value of derivative assets	0	0
Other current liabilities and other non-current liabilities | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	1,519	2,046
Other current liabilities and other non-current liabilities | Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	918	1,561
Other current liabilities and other non-current liabilities | Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	$ 601	$ 485