Consolidated Statements of Income (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Revenues	$ 5,062	$ 4,790	$ 10,064	$ 9,323
Operating expenses:
Compensation and benefits	1,078	1,072	2,195	2,147
Fuel	1,102	1,096	2,197	2,035
Purchased services	614	549	1,183	1,096
Depreciation and amortization	470	450	933	896
Equipment rents	199	191	401	383
Materials and other	161	223	452	453
Total operating expenses	3,624	3,581	7,361	7,010
Operating income	1,438	1,209	2,703	2,313
Interest expense	155	138	303	274
Other expense, net	3	1	5	4
Income before income taxes	1,280	1,070	2,395	2,035
Income tax expense	478	380	892	738
Net income	$ 802	$ 690	$ 1,503	$ 1,297