Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Revenues	$ 5,904	$ 5,847	$ 17,303	$ 17,694
Operating expenses:
Compensation and benefits	1,407	1,406	4,140	4,129
Fuel	799	863	2,475	2,660
Depreciation and amortization	648	657	1,975	1,957
Purchased services	517	615	1,528	1,836
Equipment rents	185	171	532	511
Materials and other	293	329	1,055	1,129
Total operating expenses	3,849	4,041	11,705	12,222
Operating income	2,055	1,806	5,598	5,472
Interest expense	275	269	807	782
Other (income) expense, net	(66)	(71)	(196)	(182)
Income before income taxes	1,846	1,608	4,987	4,872
Income Tax Expense (Benefit)	463	387	1,234	1,140
Net income	$ 1,383	$ 1,221	$ 3,753	$ 3,732