Derivative Instruments - Adjustments Related to Fair Value Hedges included in Net Interest Expense in Consolidated Statements of Income (Detail) - Interest rate - Interest expense, net - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Oct. 03, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest rate swaps	$ (211)	$ 18	$ 60
Gain (loss) on hedged borrowings	$ 211	$ (18)	$ (60)