Pension and Other Benefit Programs - Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions		12 Months Ended
		Sep. 27, 2025	Sep. 28, 2024	Sep. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Total other costs (benefit)		$ (261)	$ (404)	$ (340)
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost		264	248	282
Interest cost		$ 783	$ 834	$ 784
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		$ (1,161)	$ (1,138)	$ (1,149)
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]	$ 3	$ 8	$ 8
Recognized net actuarial loss/(gain)		$ 247	$ 21	$ 19
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)		$ (128)	$ (275)	$ (338)
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)		$ 136	$ (27)	$ (56)
Postretirement Medical Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost		1	1	5
Interest cost		$ 45	$ 55	$ 81
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		$ (59)	$ (58)	$ (61)
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)	$ (90)	$ 0
Recognized net actuarial loss/(gain)		$ (29)	$ (36)	$ (22)
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)		$ (133)	$ (129)	$ (2)
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)		$ (132)	$ (128)	$ 3

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