Post-Employment Benefits - Summary of Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Plan Assets at Fair Value
Plan assets at fair value, January 1	$ 13,373
Plan assets at fair value, December 31	14,420	$ 13,373
Long-term liabilities	(1,880)	(1,964)
Defined Benefit Plans
Projected Benefit Obligations
Projected benefit obligations, January 1	10,030	9,167
Service cost — benefits earned during the year	242	230	$ 374
Interest cost on projected benefit obligations	469	455	300
(Gains) losses, primarily changes in discount rates, plan design changes, law changes and differences between actual and estimated health care costs	(763)	458
Benefits paid	(398)	(377)
Other, including foreign currency translation	(130)	97
Projected benefit obligations, December 31	9,450	10,030	9,167
Plan Assets at Fair Value
Plan assets at fair value, January 1	13,085	11,373
Actual return (loss) on plan assets	1,259	1,611
Company contributions	349	349
Benefits paid	(398)	(377)
Other, including foreign currency translation	(152)	129
Plan assets at fair value, December 31	14,143	13,085	11,373
Projected benefit obligations less (greater) than plan assets, December 31	4,693	3,055
Long-term assets	5,724	4,164
Short-term liabilities	(38)	(36)
Long-term liabilities	(993)	(1,073)
Net asset (liability)	4,693	3,055
Amounts Recognized in Accumulated Other Comprehensive Income (loss):
Actuarial losses, net	772	1,751
Prior service costs (credits)	5	6
Total	777	1,757
Medical and Dental Plans
Projected Benefit Obligations
Projected benefit obligations, January 1	1,181	1,126
Service cost — benefits earned during the year	39	38	50
Interest cost on projected benefit obligations	54	59	36
(Gains) losses, primarily changes in discount rates, plan design changes, law changes and differences between actual and estimated health care costs	(33)	35
Benefits paid	(73)	(77)
Other, including foreign currency translation	(2)	0
Projected benefit obligations, December 31	1,166	1,181	1,126
Plan Assets at Fair Value
Plan assets at fair value, January 1	288	302
Actual return (loss) on plan assets	26	26
Company contributions	36	37
Benefits paid	(73)	(77)
Other, including foreign currency translation	0	0
Plan assets at fair value, December 31	277	288	$ 302
Projected benefit obligations less (greater) than plan assets, December 31	(889)	(893)
Long-term assets	0	0
Short-term liabilities	(2)	(2)
Long-term liabilities	(887)	(891)
Net asset (liability)	(889)	(893)
Amounts Recognized in Accumulated Other Comprehensive Income (loss):
Actuarial losses, net	29	62
Prior service costs (credits)	(8)	(22)
Total	$ 21	$ 40