Pension and Other Benefit Programs - Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions		12 Months Ended
		Sep. 28, 2024	Sep. 30, 2023	Oct. 01, 2022
Defined Benefit Plan Disclosure [Line Items]
Total other costs (benefit)		$ (404)	$ (340)	$ (62)
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost		248	282	400
Interest cost		$ 834	$ 784	$ 500
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]		Interest expense, net	Interest expense, net	Interest expense, net
Expected return on plan assets		$ (1,138)	$ (1,149)	$ (1,174)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Interest expense, net	Interest expense, net	Interest expense, net
Amortization of Prior-Year Service Cost (Credit)	[1]	$ 8	$ 8	$ 7
Recognized net actuarial loss/(gain)		$ 21	$ 19	$ 585
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Interest expense, net	Interest expense, net	Interest expense, net
Total other costs (benefit)		$ (275)	$ (338)	$ (82)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]		Interest expense, net	Interest expense, net	Interest expense, net
Net periodic benefit cost (benefit)		$ (27)	$ (56)	$ 318
Postretirement Medical Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost		1	5	9
Interest cost		$ 55	$ 81	$ 51
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Interest Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]		Interest expense, net	Interest expense, net	Interest expense, net
Expected return on plan assets		$ (58)	$ (61)	$ (59)
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Expected Return (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Interest expense, net	Interest expense, net	Interest expense, net
Amortization of Prior-Year Service Cost (Credit)	[1]	$ (90)	$ 0	$ 0
Recognized net actuarial loss/(gain)		$ (36)	$ (22)	$ 28
Defined Benefit Plan, Net Periodic Benefit (Cost) Credit, Amortization of Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Interest expense, net	Interest expense, net	Interest expense, net
Total other costs (benefit)		$ (129)	$ (2)	$ 20
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Excluding Service Cost, Statement of Income or Comprehensive Income [Extensible Enumeration]		Interest expense, net	Interest expense, net	Interest expense, net
Net periodic benefit cost (benefit)		$ (128)	$ 3	$ 29

[1] The amortization of prior-year service credits is related to a change in postretirement medical benefit options.