Pension and Postretirement Benefit Plans - Components of Net Periodic Benefit Cost and Other Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Non-operating expense
Total net periodic benefit cost (benefit)	$ (129)	$ (248)	$ (297)
Postretirement Benefits
Operating expense
Service cost	27	42	53
Non-operating expense
Interest cost	87	52	43
Expected return on plan assets	(77)	(72)	(78)
Amortization of transition asset	0	0	0
Amortization of prior service benefit	(31)	(31)	(33)
Amortization of net actuarial loss	9	40	56
Settlements, curtailments, special termination benefits and other	0	2	3
Total non-operating expense (benefit)	(12)	(9)	(9)
Total net periodic benefit cost (benefit)	15	33	44
Other changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Amortization of transition asset	0	0	0
Prior service cost (benefit)	0	0	0
Amortization of prior service benefit	31	31	33
Net actuarial (gain) loss	100	(166)	(104)
Amortization of net actuarial loss	(9)	(40)	(56)
Foreign currency	0	2	(1)
Settlements, curtailments, special termination benefits and other	0	(2)	(3)
Total recognized in other comprehensive (income) loss	122	(175)	(131)
Total recognized in net periodic benefit cost (benefit) and other comprehensive (income) loss	137	(142)	(87)
United States | U.S. Pension Plans
Operating expense
Service cost	171	256	286
Non-operating expense
Interest cost	662	417	360
Expected return on plan assets	(974)	(963)	(1,055)
Amortization of transition asset	0	0	0
Amortization of prior service benefit	(24)	(24)	(24)
Amortization of net actuarial loss	292	424	529
Settlements, curtailments, special termination benefits and other	(5)	12	24
Total non-operating expense (benefit)	(49)	(134)	(166)
Total net periodic benefit cost (benefit)	122	122	120
Other changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Amortization of transition asset	0	0	0
Prior service cost (benefit)	0	0	0
Amortization of prior service benefit	24	24	24
Net actuarial (gain) loss	495	61	(614)
Amortization of net actuarial loss	(292)	(424)	(529)
Foreign currency	0	0	0
Settlements, curtailments, special termination benefits and other	5	(12)	(23)
Total recognized in other comprehensive (income) loss	232	(351)	(1,142)
Total recognized in net periodic benefit cost (benefit) and other comprehensive (income) loss	354	(229)	(1,022)
International | U.S. Pension Plans
Operating expense
Service cost	76	128	164
Non-operating expense
Interest cost	225	125	98
Expected return on plan assets	(307)	(271)	(326)
Amortization of transition asset	2	2	2
Amortization of prior service benefit	2	0	(3)
Amortization of net actuarial loss	7	29	104
Settlements, curtailments, special termination benefits and other	3	10	3
Total non-operating expense (benefit)	(68)	(105)	(122)
Total net periodic benefit cost (benefit)	8	23	42
Other changes in plan assets and benefit obligations recognized in other comprehensive (income) loss
Amortization of transition asset	(2)	(2)	(2)
Prior service cost (benefit)	(1)	8	1
Amortization of prior service benefit	(2)	0	3
Net actuarial (gain) loss	166	(689)	(434)
Amortization of net actuarial loss	(7)	(29)	(104)
Foreign currency	3	(82)	(71)
Settlements, curtailments, special termination benefits and other	0	(4)	(1)
Total recognized in other comprehensive (income) loss	157	(798)	(608)
Total recognized in net periodic benefit cost (benefit) and other comprehensive (income) loss	$ 165	$ (775)	$ (566)