Pension and Postretirement Benefit Plans - Components of Net Periodic Benefit Cost and Other Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Non-operating expense
Total net periodic benefit cost (benefit)	$ (11)	$ (31)
Postretirement Benefits
Operating expense
Service cost	7	6
Non-operating expense
Interest cost	22	22
Expected return on plan assets	(19)	(19)
Amortization of transition asset	0	0
Amortization of prior service benefit	(6)	(8)
Amortization of net actuarial loss	6	2
Total non-operating expense (benefit)	3	(3)
Total net periodic benefit cost (benefit)	10	3
United States | U.S. Pension Plans
Operating expense
Service cost	37	43
Non-operating expense
Interest cost	160	166
Expected return on plan assets	(237)	(244)
Amortization of transition asset	0	0
Amortization of prior service benefit	(4)	(6)
Amortization of net actuarial loss	95	73
Total non-operating expense (benefit)	14	(11)
Total net periodic benefit cost (benefit)	51	32
International | U.S. Pension Plans
Operating expense
Service cost	21	19
Non-operating expense
Interest cost	54	55
Expected return on plan assets	(87)	(75)
Amortization of transition asset	1	0
Amortization of prior service benefit	1	1
Amortization of net actuarial loss	3	2
Total non-operating expense (benefit)	(28)	(17)
Total net periodic benefit cost (benefit)	$ (7)	$ 2