Segment Reporting - Information on Reportable Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 1,421	$ 1,040	$ 4,273	$ 2,883
Cost of transportation and services (exclusive of depreciation and amortization)	1,137	809	3,408	2,208
Direct operating expense (exclusive of depreciation and amortization)	48	49	143	152
Sales, general and administrative expense	208	149	632	448
Depreciation and amortization expense	26	21	88	54
Transaction and integration costs	5	30	18	38
Other expense (income)	1	(216)	(1)	(217)
Interest expense, net	9	6	26	22
Loss before income taxes	(15)	(242)	(64)	(271)
Reportable Segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Depreciation and amortization expense	26	21	88	54
Transaction and integration costs	5	30	18	38
Restructuring and other costs	7	2	24	18
Other expense (income)	(2)	217	0	217
Interest expense, net	9	6	26	22
Loss before income taxes	(15)	(242)	(64)	(271)
Reportable Segment | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	1,421	1,040	4,273	2,883
Cost of transportation and services (exclusive of depreciation and amortization)	1,137	809	3,408	2,208
Direct operating expense (exclusive of depreciation and amortization)	48	49	143	152
Sales, general and administrative expense	197	149	602	436
Other expense	1	(1)	1	0
Segment adjusted EBITDA	38	34	119	87
Reportable Segment | Segment Reporting, Reconciling Item, Corporate Nonsegment
Segment Reporting, Revenue Reconciling Item [Line Items]
Unallocated corporate expenses	$ 8	$ 0	$ 27	$ 9