Pension and Other Postretirement Benefit Plans - Net Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 8	$ 12	$ 17	$ 25
Interest cost	16	11	31	23
Expected return on plan assets	(16)	(21)	(32)	(43)
Amortization of unrecognized prior service cost (credit)	(12)	(14)	(25)	(29)
Net (gain) loss amortization	(11)	(11)	(21)	(21)
Net periodic benefit cost	(15)	(23)	(30)	(45)
U.S. | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	76	99	152	198
Interest cost	133	103	266	206
Expected return on plan assets	(185)	(197)	(372)	(393)
Amortization of unrecognized prior service cost (credit)	0	(8)	(1)	(16)
Net (gain) loss amortization	0	56	0	112
Termination benefits	1	1	1	1
Curtailments	2	4	5	8
Settlements	5	101	26	101
Net periodic benefit cost	32	159	77	217
International | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	50	72	99	147
Interest cost	75	37	149	75
Expected return on plan assets	(130)	(98)	(257)	(199)
Amortization of unrecognized prior service cost (credit)	16	(3)	12	(7)
Net (gain) loss amortization	(1)	25	(2)	50
Termination benefits	0	0	0	0
Curtailments	0	0	0	0
Settlements	0	0	0	0
Net periodic benefit cost	$ 10	$ 33	$ 1	$ 66