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. 28, 2019	Sep. 29, 2018	Sep. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on interest rate swaps	$ 337	$ (230)	$ (211)
Gain (loss) on hedged borrowings	(337)	230	211
Derivative, Gain (Loss) on Derivative, Net	$ (58)	$ (15)	$ 35