Condensed Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Income Statement [Abstract]
Revenue	$ 2,096	$ 1,954
Salaries, wages and employee benefits	880	832
Purchased transportation	423	399
Fuel, operating expenses and supplies	423	393
Operating taxes and licenses	21	19
Insurance and claims	34	35
Gains on sales of property and equipment	(1)	(2)
Depreciation and amortization expense	131	123
Legal matters	0	(11)
Transaction and integration costs	2	3
Restructuring costs	9	12
Operating income	174	151
Other income	(3)	(1)
Debt extinguishment loss	0	5
Interest expense	53	56
Income before income tax provision	124	91
Income tax provision	23	22
Net income	$ 101	$ 69
Earnings per share data
Basic earnings per share (in dollars per share)	$ 0.87	$ 0.59
Diluted earnings per share (in dollars per share)	$ 0.85	$ 0.58
Weighted-average common shares outstanding
Basic weighted-average common shares outstanding (in shares)	117	117
Diluted weighted-average common shares outstanding (in shares)	119	120

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482099/360-10-50-1