Post-Employment Benefits - Summary of Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Plan Assets at Fair Value
Plan assets at fair value, January 1	$ 13,838
Plan assets at fair value, December 31	11,675	$ 13,838
Long-term liabilities	(1,784)	(2,738)
Defined Benefit Plans
Projected Benefit Obligations
Projected benefit obligations, January 1	12,773	13,129
Service cost — benefits earned during the year	374	391	$ 336
Interest cost on projected benefit obligations	300	248	300
(Gains) losses, primarily changes in discount rates, plan design changes, law changes and differences between actual and estimated health care costs	(3,645)	(463)
Benefits paid	(368)	(340)
Other, including foreign currency translation	(267)	(192)
Projected benefit obligations, December 31	9,167	12,773	13,129
Plan Assets at Fair Value
Plan assets at fair value, January 1	13,468	12,018
Actual return (loss) on plan assets	(1,856)	1,521
Company contributions	413	418
Benefits paid	(368)	(340)
Other, including foreign currency translation	(284)	(149)
Plan assets at fair value, December 31	11,373	13,468	12,018
Projected benefit obligations less (greater) than plan assets, December 31	2,206	695
Long-term assets	3,200	2,270
Short-term liabilities	(32)	(31)
Long-term liabilities	(962)	(1,544)
Net asset (liability)	2,206	695
Amounts Recognized in Accumulated Other Comprehensive Income (loss):
Actuarial losses, net	1,960	3,062
Prior service cost (credits)	(6)	(5)
Total	1,954	3,057
Medical and Dental Plans
Projected Benefit Obligations
Projected benefit obligations, January 1	1,566	1,567
Service cost — benefits earned during the year	50	56	46
Interest cost on projected benefit obligations	36	33	42
(Gains) losses, primarily changes in discount rates, plan design changes, law changes and differences between actual and estimated health care costs	(437)	(16)
Benefits paid	(70)	(74)
Other, including foreign currency translation	(19)	0
Projected benefit obligations, December 31	1,126	1,566	1,567
Plan Assets at Fair Value
Plan assets at fair value, January 1	370	353
Actual return (loss) on plan assets	(33)	56
Company contributions	35	35
Benefits paid	(70)	(74)
Other, including foreign currency translation	0	0
Plan assets at fair value, December 31	302	370	$ 353
Projected benefit obligations less (greater) than plan assets, December 31	(824)	(1,196)
Long-term assets	0	0
Short-term liabilities	(2)	(2)
Long-term liabilities	(822)	(1,194)
Net asset (liability)	(824)	(1,196)
Amounts Recognized in Accumulated Other Comprehensive Income (loss):
Actuarial losses, net	27	412
Prior service cost (credits)	(33)	(39)
Total	$ (6)	$ 373