Derivative Instruments - Net Gains or Losses Recognized in Costs and Expenses on Economic Exposures Associated with Foreign Currency Exchange Rates (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Oct. 03, 2015
Costs and Expenses
Derivative [Line Items]
Net gains (losses) on foreign currency denominated assets and liabilities	$ 105	$ 2	$ (574)
Net gains (losses) on foreign exchange risk management contracts not designated as hedges	(120)	(65)	558
Net gains (losses)	(15)	(63)	(16)
Interest expense, net
Derivative [Line Items]
Net gains (losses) on foreign currency denominated assets and liabilities	(13)	(2)	42
Net gains (losses) on foreign exchange risk management contracts not designated as hedges	11	0	(43)
Net gains (losses)	(2)	(2)	(1)
Income Taxes
Derivative [Line Items]
Net gains (losses) on foreign currency denominated assets and liabilities	3	49	40
Net gains (losses) on foreign exchange risk management contracts not designated as hedges	24	(24)	0
Net gains (losses)	$ 27	$ 25	$ 40