Consolidated Statements of Income (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues	$ 5,284	$ 5,002
Operating expenses:
Compensation and benefits	1,139	1,117
Fuel	1,122	1,095
Purchased services	617	569
Depreciation and amortization	483	463
Equipment rents	198	202
Materials and other	257	291
Total operating expenses	3,816	3,737
Operating income	1,468	1,265
Interest expense	178	148
Other expense, net	1	2
Income before income taxes	1,289	1,115
Income tax expense	491	414
Net income	$ 798	$ 701