Pension and Other Benefit Programs - Benefit Obligations, Assets, Funded Status and Balance Sheet Impacts Associated with Pension and Postretirement Medical Benefit Plans based upon Actuarial Valuations (Detail) - USD ($) $ in Millions		12 Months Ended
		Oct. 02, 2021	Oct. 03, 2020	Sep. 28, 2019
Fair value of plans' assets
Contributions		$ 612
Amounts recognized in the balance sheet
Non-current liabilities		(4,132)	$ (6,451)
Net balance sheet liability		(4,111)
Pension Plans
Projected benefit obligations
Beginning obligations		(20,760)	(18,531)
Service cost		(434)	(410)	$ (345)
Interest cost		(457)	(527)	(592)
Actuarial (loss) gain	[1]	15	(1,958)
Plan amendments and other		20	1
Benefits Paid		661	662
Curtailments		0	3
Ending obligations		(20,955)	(20,760)	(18,531)
Fair value of plans' assets
Beginning fair value		15,598	14,878
Actual return on plan assets		2,653	770
Contributions		565	664
Benefits paid		(661)	(662)
Expenses and other		79	52
Ending fair value		18,076	15,598	14,878
Underfunded status of the plans		(2,879)	(5,162)
Amounts recognized in the balance sheet
Non-current assets		88	20
Current liabilities		(63)	(59)
Non-current liabilities		(2,904)	(5,123)
Net balance sheet liability		(2,879)	(5,162)
Postretirement Medical Plans
Projected benefit obligations
Beginning obligations		(2,104)	(1,946)
Service cost		(10)	(10)	(8)
Interest cost		(47)	(56)	(67)
Actuarial (loss) gain	[1]	(13)	(127)
Plan amendments and other		(14)	(12)
Benefits Paid		67	47
Curtailments		0	0
Ending obligations		(2,121)	(2,104)	(1,946)
Fair value of plans' assets
Beginning fair value		771	762
Actual return on plan assets		137	38
Contributions		47	9
Benefits paid		(67)	(47)
Expenses and other		1	9
Ending fair value		889	771	$ 762
Underfunded status of the plans		(1,232)	(1,333)
Amounts recognized in the balance sheet
Non-current assets		0	0
Current liabilities		(4)	(5)
Non-current liabilities		(1,228)	(1,328)
Net balance sheet liability		$ (1,232)	$ (1,333)

[1] The actuarial loss for 2020 was primarily due to a reduction in the discount rate from the rate that was used in the preceding fiscal year.