Postretirement Plans - Schedule of Changes in the Benefit Obligation, Plan Assets and Funded Status of Pensions and OPB (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Accrued pension plan liability, net	$ (5,997)	$ (6,516)
Pension
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	54,325	55,117
Service cost	5	2	$ 3
Interest cost	2,635	2,820	2,080
Amendments	140
Actuarial (gain)/loss	(2,493)	1,217
Gross benefits paid	(4,173)	(4,837)
Subsidies
Exchange rate adjustment	(18)	6
Ending balance	50,421	54,325	55,117
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance at fair value	48,891	49,825
Actual return on plan assets	738	3,756
Plan participants' contributions
Benefits paid	(4,034)	(4,698)
Exchange rate adjustment	(21)	8
Ending balance at fair value	45,574	48,891	49,825
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Other assets	1,289	1,219
Accrued liabilities	(139)	(137)
Accrued retiree health care
Accrued pension plan liability, net	(5,997)	(6,516)
Net amount recognized	(4,847)	(5,434)
Other Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Beginning balance	2,651	2,978
Service cost	51	49	72
Interest cost	124	148	98
Amendments
Actuarial (gain)/loss	156	(152)
Gross benefits paid	(336)	(375)
Subsidies	8	2
Exchange rate adjustment	(3)	1
Ending balance	2,651	2,651	2,978
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Beginning balance at fair value	163	140
Actual return on plan assets	22	23
Plan participants' contributions	1	4
Benefits paid	(3)	(4)
Exchange rate adjustment
Ending balance at fair value	183	163	$ 140
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract]
Other assets	21	81
Accrued liabilities	(313)	(336)
Accrued retiree health care	(2,176)	(2,233)
Accrued pension plan liability, net
Net amount recognized	$ (2,468)	$ (2,488)