Financial Instruments - Derivative Instruments at Gross Fair Value (Details) - Level 2 - USD ($) $ in Millions	Sep. 30, 2017	Sep. 24, 2016
Other current assets and other non-current assets | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	$ 1,412	$ 671
Other current assets and other non-current assets | Interest rate contracts
Derivative assets:
Fair value of derivative assets	218	728
Other current assets and other non-current assets | Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	1,049	518
Other current assets and other non-current assets | Derivatives designated as accounting hedges | Interest rate contracts
Derivative assets:
Fair value of derivative assets	218	728
Other current assets and other non-current assets | Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	363	153
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
Accrued expenses and other non-current liabilities | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	1,260	1,069
Accrued expenses and other non-current liabilities | Interest rate contracts
Derivative liabilities:
Fair value of derivative liabilities	303	7
Accrued expenses and other non-current liabilities | Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	759	935
Accrued expenses and other non-current liabilities | Derivatives designated as accounting hedges | Interest rate contracts
Derivative liabilities:
Fair value of derivative liabilities	303	7
Accrued expenses and other non-current liabilities | Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	501	134
Accrued expenses and other non-current liabilities | Derivatives not designated as accounting hedges | Interest rate contracts
Derivative liabilities:
Fair value of derivative liabilities	$ 0	$ 0