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, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Non-operating expense
Total net periodic benefit cost (benefit)	$ (31)	$ (67)	$ (62)	$ (134)
Postretirement Benefits
Operating expense
Service cost	6	10	12	21
Non-operating expense
Interest cost	23	13	45	26
Expected return on plan assets	(19)	(17)	(38)	(35)
Amortization of transition asset	0	0	0	0
Amortization of prior service benefit	(8)	(9)	(16)	(16)
Amortization of net actuarial loss	2	10	4	20
Settlements, curtailments, special termination benefits and other	0	1	0	2
Total non-operating expense (benefit)	(2)	(2)	(5)	(3)
Total net periodic benefit cost (benefit)	4	8	7	18
United States | Qualified and Non-qualified Pension Benefits
Operating expense
Service cost	43	64	86	128
Non-operating expense
Interest cost	165	104	331	208
Expected return on plan assets	(244)	(241)	(488)	(482)
Amortization of transition asset	0	0	0	0
Amortization of prior service benefit	(6)	(6)	(12)	(12)
Amortization of net actuarial loss	74	106	147	212
Settlements, curtailments, special termination benefits and other	0	0	0	0
Total non-operating expense (benefit)	(11)	(37)	(22)	(74)
Total net periodic benefit cost (benefit)	32	27	64	54
International | Qualified and Non-qualified Pension Benefits
Operating expense
Service cost	20	33	39	68
Non-operating expense
Interest cost	54	32	109	64
Expected return on plan assets	(75)	(70)	(150)	(142)
Amortization of transition asset	1	1	1	1
Amortization of prior service benefit	0	0	1	0
Amortization of net actuarial loss	2	9	4	20
Settlements, curtailments, special termination benefits and other	0	0	0	0
Total non-operating expense (benefit)	(18)	(28)	(35)	(57)
Total net periodic benefit cost (benefit)	$ 2	$ 5	$ 4	$ 11