Financial Instruments - Derivative Instruments at Gross Fair Value (Details) - Level 2 - USD ($) $ in Millions	Dec. 29, 2018	Sep. 29, 2018
Other current assets and other non-current assets | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	$ 1,529	$ 1,274
Other current assets and other non-current assets | Interest rate contracts
Derivative assets:
Fair value of derivative assets	22
Other current assets and other non-current assets | Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	1,110	1,015
Other current assets and other non-current assets | Derivatives designated as accounting hedges | Interest rate contracts
Derivative assets:
Fair value of derivative assets	22
Other current assets and other non-current assets | Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	419	259
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
Other current liabilities and other non-current liabilities | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	1,046	680
Other current liabilities and other non-current liabilities | Interest rate contracts
Derivative liabilities:
Fair value of derivative liabilities	821	1,456
Other current liabilities and other non-current liabilities | Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	701	543
Other current liabilities and other non-current liabilities | Derivatives designated as accounting hedges | Interest rate contracts
Derivative liabilities:
Fair value of derivative liabilities	821	1,456
Other current liabilities and other non-current liabilities | Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	345	137
Other current liabilities and other non-current liabilities | Derivatives not designated as accounting hedges | Interest rate contracts
Derivative liabilities:
Fair value of derivative liabilities	$ 0	$ 0