Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues	$ 4,585	$ 5,369	$ 9,352	$ 10,971
Operating expenses:
Compensation and benefits	1,134	1,268	2,342	2,606
Purchased services	589	628	1,227	1,276
Depreciation and amortization	530	489	1,050	985
Fuel	431	697	826	1,410
Equipment rents	184	207	372	398
Materials and other	230	311	543	633
Total operating expenses	3,098	3,600	6,360	7,308
Operating income	1,487	1,769	2,992	3,663
Interest expense	249	228	494	445
Other expense, net	0	5	2	10
Income before income taxes	1,238	1,536	2,496	3,208
Income tax expense	466	573	940	1,200
Net income	$ 772	$ 963	$ 1,556	$ 2,008