Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues	$ 5,314	$ 5,167	$ 15,749	$ 14,519
Operating expenses:
Compensation and benefits	1,160	1,193	3,685	3,535
Purchased services	608	562	1,843	1,789
Fuel	595	533	1,777	1,359
Depreciation and amortization	591	534	1,756	1,584
Equipment rents	193	198	585	570
Materials and other	214	267	769	810
Total operating expenses	3,361	3,287	10,415	9,647
Operating income	1,953	1,880	5,334	4,872
Interest expense	253	250	761	744
Other (income) expense, net	(10)	(3)	(19)	(1)
Income before income taxes	1,710	1,633	4,592	4,129
Income tax expense	668	613	1,754	1,553
Net income	$ 1,042	$ 1,020	$ 2,838	$ 2,576