Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues	$ 6,147	$ 5,314	$ 17,649	$ 15,749
Operating expenses:
Compensation and benefits	1,378	1,173	4,021	3,725
Purchased services	718	608	2,124	1,843
Fuel	859	595	2,456	1,777
Depreciation and amortization	580	591	1,726	1,756
Equipment rents	183	193	542	585
Materials and other	320	214	1,041	769
Total operating expenses	4,038	3,374	11,910	10,455
Operating income	2,109	1,940	5,739	5,294
Interest expense	262	253	774	761
Other (income) expense, net	(32)	(23)	(82)	(59)
Income before income taxes	1,879	1,710	5,047	4,592
Income tax expense	486	668	1,200	1,754
Net income	$ 1,393	$ 1,042	$ 3,847	$ 2,838