Casualty, Environmental and Other Reserves - Schedule of Casualty, Environmental and Other Reserves (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Loss Contingencies [Line Items]
Current	$ 148	$ 144	[1]
Long-term	299	296	[1]
Total	447	440
Total Casualty
Loss Contingencies [Line Items]
Current	62	52
Long-term	138	143
Total	200	195
Personal Injury
Loss Contingencies [Line Items]
Current	51	45
Long-term	82	83
Total	133	128
Occupational
Loss Contingencies [Line Items]
Current	11	7
Long-term	56	60
Total	67	67
Environmental
Loss Contingencies [Line Items]
Current	36	41
Long-term	113	113
Total	149	154
Other
Loss Contingencies [Line Items]
Current	50	51
Long-term	48	40
Total	$ 98	$ 91

[1] See Note 11, Revision of Prior Period Financial Statements.