Pension and Postretirement Benefit Plans - Components of Net Periodic Benefit Cost and Other Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Non-operating expense
Total net periodic benefit cost (benefit)	$ 796	$ (25)	$ 785	$ (51)
Postretirement Benefits
Operating expense
Service cost	5	6	12	12
Non-operating expense
Interest cost	21	23	43	45
Expected return on plan assets	(15)	(19)	(34)	(38)
Amortization of transition asset	0	0	0	0
Amortization of prior service benefit	(6)	(8)	(12)	(16)
Amortization of net actuarial loss	4	2	10	4
Settlements, curtailments, special termination benefits and other	0	0	0	0
Total non-operating expense (benefit)	4	(2)	7	(5)
Total net periodic benefit cost (benefit)	9	4	19	7
Postretirement Benefits | Continuing Operations
Operating expense
Service cost	5	5	11	10
Non-operating expense
Total non-operating expense (benefit)	4	(2)	7	(4)
Total net periodic benefit cost (benefit)	9	3	18	6
Postretirement Benefits | Discontinued Operations
Operating expense
Service cost	0	1	1	2
Non-operating expense
Total non-operating expense (benefit)	0	0	0	(1)
Total net periodic benefit cost (benefit)	0	1	1	1
United States | U.S. Pension Plans
Operating expense
Service cost	29	43	66	86
Non-operating expense
Interest cost	141	165	301	331
Expected return on plan assets	(196)	(244)	(433)	(488)
Amortization of transition asset	0	0	0	0
Amortization of prior service benefit	(4)	(6)	(8)	(12)
Amortization of net actuarial loss	83	74	178	147
Settlements, curtailments, special termination benefits and other	795	0	795	0
Total non-operating expense (benefit)	819	(11)	833	(22)
Total net periodic benefit cost (benefit)	848	32	899	64
United States | U.S. Pension Plans | Continuing Operations
Operating expense
Service cost	29	35	59	70
Non-operating expense
Total non-operating expense (benefit)	819	(7)	833	(14)
Total net periodic benefit cost (benefit)	848	28	892	56
United States | U.S. Pension Plans | Discontinued Operations
Operating expense
Service cost	0	8	7	16
Non-operating expense
Total non-operating expense (benefit)	0	(4)	0	(8)
Total net periodic benefit cost (benefit)	0	4	7	8
International | U.S. Pension Plans
Operating expense
Service cost	14	20	35	39
Non-operating expense
Interest cost	49	54	103	109
Expected return on plan assets	(80)	(75)	(167)	(150)
Amortization of transition asset	1	1	2	1
Amortization of prior service benefit	0	0	1	1
Amortization of net actuarial loss	3	2	6	4
Settlements, curtailments, special termination benefits and other	0	0	0	0
Total non-operating expense (benefit)	(27)	(18)	(55)	(35)
Total net periodic benefit cost (benefit)	(13)	2	(20)	4
International | U.S. Pension Plans | Continuing Operations
Operating expense
Service cost	14	16	30	31
Non-operating expense
Total non-operating expense (benefit)	(27)	(16)	(55)	(33)
Total net periodic benefit cost (benefit)	(13)	0	(25)	(2)
International | U.S. Pension Plans | Discontinued Operations
Operating expense
Service cost	0	4	5	8
Non-operating expense
Total non-operating expense (benefit)	0	(2)	0	(2)
Total net periodic benefit cost (benefit)	$ 0	$ 2	$ 5	$ 6