Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenues	$ 23,437	$ 23,876	$ 25,888
Operating expenses:
Compensation and benefits	5,872	5,551	5,321
Fuel	3,267	3,684	4,581
Depreciation and amortization	2,635	2,625	2,528
Purchased services	2,086	2,396	2,697
Equipment rents	715	699	720
Materials and other	1,390	1,522	1,441
Total operating expenses	15,965	16,477	17,288
Operating income	7,472	7,399	8,600
Interest expense	1,078	1,048	1,025
Other (income) expense, net	(254)	(263)	(133)
Income before income taxes	6,648	6,614	7,708
Income tax expense	1,617	1,527	1,762
Net income	$ 5,031	$ 5,087	$ 5,946