Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Income Statement [Abstract]
Revenues	$ 5,970	$ 5,693
Operating expenses:
Compensation and benefits	1,374	1,387
Fuel	768	770
Depreciation and amortization	695	675
Purchased services	553	538
Equipment rents	178	182
Materials and other	356	321
Total operating expenses	3,924	3,873
Operating income	2,046	1,820
Interest expense	277	272
Other (income) expense, net	(51)	(55)
Income before income taxes	1,820	1,603
Income Tax Expense (Benefit)	443	389
Net income	$ 1,377	$ 1,214