Casualty, Environmental and Other Reserves - Schedule of Casualty, Environmental and Other Reserves (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Loss Contingencies [Line Items]
Current	$ 146	$ 149
Long-term	319	313
Total	465	462
Total Casualty
Loss Contingencies [Line Items]
Current	58	58
Long-term	152	150
Total	210	208
Personal Injury
Loss Contingencies [Line Items]
Current	51	51
Long-term	93	91
Total	144	142
Occupational
Loss Contingencies [Line Items]
Current	7	7
Long-term	59	59
Total	66	66
Environmental
Loss Contingencies [Line Items]
Current	37	37
Long-term	114	114
Total	151	151
Other
Loss Contingencies [Line Items]
Current	51	54
Long-term	53	49
Total	$ 104	$ 103