Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Income Statement [Abstract]
Revenues	$ 23,421	$ 23,437	$ 23,876
Operating expenses:
Compensation and benefits	5,531	5,872	5,551
Fuel	3,011	3,267	3,684
Depreciation and amortization	2,737	2,635	2,625
Purchased services	2,168	2,086	2,396
Equipment rents	709	715	699
Materials and other	1,210	1,390	1,522
Total operating expenses	15,366	15,965	16,477
Operating income	8,055	7,472	7,399
Interest expense	1,098	1,078	1,048
Other (income) expense, net	(218)	(254)	(263)
Income before income taxes	7,175	6,648	6,614
Income tax expense	1,699	1,617	1,527
Net income	$ 5,476	$ 5,031	$ 5,087