Consolidated Statements of Income (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenues	$ 5,343	$ 4,961	$ 15,407	$ 14,284
Operating expenses:
Compensation and benefits	1,149	1,069	3,344	3,216
Fuel	1,089	1,089	3,286	3,124
Purchased services	601	571	1,784	1,667
Depreciation and amortization	475	454	1,408	1,350
Equipment rents	204	192	605	575
Materials and other	156	206	608	659
Total operating expenses	3,674	3,581	11,035	10,591
Operating income	1,669	1,380	4,372	3,693
Interest expense	157	142	460	416
Other expense, net	4	2	9	6
Income before income taxes	1,508	1,236	3,903	3,271
Income tax expense	571	470	1,463	1,208
Net income	$ 937	$ 766	$ 2,440	$ 2,063